Install a 16 Tooth Front Sprocket

[jonathan180iq]

This is fairly simple process. It actually took more time to reinstall the friggin' cotter pin than anything else.

Things you'll need:

17mm wrench
3/4" wrench
12mm socket
7mm socket
30mm socket (torque wrench)
alligator pliers
flat head screw driver
new sprocket


http://upload8.postimage.org/26572/DSCN6780.jpg (http://upload8.postimage.org/26572/photo_hosting.html)

PUT YOUR BIKE ON SOME STANDS

http://upload8.postimage.org/26608/DSCN6463.jpg (http://upload8.postimage.org/26608/photo_hosting.html)


The first thing that I did was remove the sprocket cover. There are three 7mm bolts that hold the cover on. They don't need to be torqued or anything.

http://upload8.postimage.org/26591/DSCN6759.jpg (http://upload8.postimage.org/26591/photo_hosting.html)

If your sprocket cover is dirty, this is probably a good time to clean the inside and remove all of the extra gunk from the chain goo.

Next, you'll want to remove the cotter pin and loosen the rear axle nuts. This is the easy part of the rear axle work.

http://upload8.postimage.org/26623/DSCN6763.jpg (http://upload8.postimage.org/26623/photo_hosting.html)

Work the chain tension bolts and loosen the chain to get some slack. YOU"LL NEED IT.

Now go back to the sprocket and bend the lock washer FLAT. This is important or you will never get the bolt off.

http://upload8.postimage.org/26637/DSCN6761.jpg (http://upload8.postimage.org/26637/photo_hosting.html)

Now, you'll need the 30mm torque wrench to get this bolt off. You'll also need to put the bike in gear and have someone press the rear brake pedal. I didn't have anyone to help. So, I sat on the bike and one handed the torque wrench.

Getting the old sprocket off is quite easy. Getting the new sprocket on isn't too hard, you just need to relax and make sure you push it on the little gear teeth with care.


http://upload8.postimage.org/26679/DSCN6772.jpg (http://upload8.postimage.org/26679/photo_hosting.html)

Slide the new sprocket on, reinstall the lock washer and bolt and tighten. You will need to make sure to REFLATTEN the lock washer once it's all good and tight.

http://upload8.postimage.org/26688/DSCN6773.jpg (http://upload8.postimage.org/26688/photo_hosting.html)

Once this is all done, retighten the chain per the manual's instruction and you're pretty much set.

You just need to reinstall the sprocket cover and YOU"RE DONE. GO FOR A RIDE!!!!

Here is a final shot of the difference between the 16 T sprocket and the original 15T sprocket

http://upload8.postimage.org/26697/DSCN6766.jpg (http://upload8.postimage.org/26697/photo_hosting.html)

[jonathan180iq]

After the first ride, all I can say is "WOW".

For those of you who think that first gear is useless, you need this new front sprocket.

I wasn't able to reach a higher top speed, but it wasn't because of the lack of engine. The extra mass of the sprocket must be holding back some of the GZ's punch, because there are plenty of revs left at 70mph. There just isn't enough grunt to carry it over the 70-75 mark quickly. I reached 75-78, but it took a while. This was on a slight incline of rolling road. IF I had a downhill, I have no dobut that I would have reached 90.

OK, the good stuff.

The gears are much more useable and cruising speed is increased without the vibration or buzziness.

1st gear is now capable of reaching 25+MPH without redlining
2nd gear will carry you to 30-35+. Again, without redlinig.
3rd gear is good for 40-46
4th gear can easily reach 60mph
5th gear will go on forever

It's important to note that these numbers come without having to goose the motor at all. These are all cruising speeds.

These numbers are'nt fantastic. However, anyone who spends a lot of time on the bike knows that the stock gearing isn't capable of reaching these speeds without frying the motor. I don't even think the stock gearing can do it while frying.

The most important part of the mod comes from the fact that riding on the highway(4 land roads) around 55-65 mph is no longer buzzy or nerveous.
The engine seems very smooth with this gearing in all gears and, again, I must stress that the increased speed comes with the engine doing less work.

I think this is a must do for anyone who spends a lot of time on the time or rides on speedier highways.

TOTAL COST= $18.95

[Dupo]

Nice job on the How To guide!

[jonathan180iq]

I'm not sure if it's too coherent. I get busy watching the Braves and that kept most of my attention.
:2tup:

[Bill]

Well done job on the "How To". Both the text and phots were very professionally done.

Cheers!

[Water Warrior 2]

Jonathan, excellant "how to" on the sprocket change. I have wondered about an extra tooth up front. Sounds like it might be the way to go. How many miles have you ridden before the change ?? And what condition were the chain and front sprocket in ??

[Badbob]

Good job. :tup:

I've been considering doing this myself but decided to wait until I replace the chain. You have convinced me to its a good thing to do. Thanks.

Did you wash the bike before you started? Seems awfully clean.

[davidc83]

Nice job. I think even I can do this. By the way, where did you buy the 16T sprocket?

[jonathan180iq]

BadBob,
were you making fun of my pollen covered rain-spot mobile? I sure hope not. The pollen count was really high for a while and I haven't really given the bike a good washing in a while.

David C83:
I bought the sprocket from www.bikebandit.com (http://www.bikebandit.com) It's a JT front sprocket. Do a search by DRIVE components and then select JT - Suzuki and you'll see the GZ250. All of the years are the same. So, if you have to choose a 2004 or something, it will work on the newer models.

Water Warrior:
I had about 1500-1600 miles on the bike before the change. It's really worth it.

I didn't have to change the chain or anything and the original sprocket wasn't worn at all. It was alittle gunky from chain goo, but it's all good now. This whole process also allowed me to readjust the cahin tension. That's always nice.

Cheers,
Jonathan

[Badbob]

BadBob,
were you making fun of my pollen covered rain-spot mobile? I sure hope not. The pollen count was really high for a while and I haven't really given the bike a good washing in a while.

Nah! Not making fun. Mine is greasy under that sprocket cover. I did notice rusty spots on the chain but not pollen.

[Jordan310]

Hey,

I noticed that the OEM Suzuki sprocket has a sort of rubber pice to it, and looks to be a bit more heavy duty.
Any reason or function that anyone can speak of for that rubber washer part on the OEM?

As well, when you said you adjusted the chain tension, by how much?
More slack, less? how much less?

Im going to do this mod myself, but I want optimal chain tension.

[Water Warrior 2]

Thr rubber is supposed to make things a little more silent overall. Most reports I have heard say little to none for noise abatement. I believe SunStar still supplies Zuk with their sprockets and they are good quality items. Shop online for the same at a lower price than your local dealer or support dealer til you need really need him. It's all a matter of choice.

[jonathan180iq]

Jordan,
I adjusted the chain tension to meet the regular specs. Check the service manual for this info. Just tighten it up to where it should be with a normal sprocket. the amount needed depends on your current chain tension.

[BadMojo]

Outstanding, excellent how to. :rawk:

[Jordan310]

Something tells me to get the Suzuki sprocket with the rubber sound deadener. I think by the looks of it it seems a bit more sturdy than the aftermarket ones, and although it may not make a major difference in sound? Im sure it makes some - in quality as well.

Dunno.

I think I can find a good salvage OEM for the same cost or less as an aftermarket.

[jonathan180iq]

There is no OEM Suzuki 16T sprocket that will fit our bike. The rubber sound deadener (if that's even what it is) has no fuction. What I mean by that is that there is no difference at all between the 16T JT sprocket and 15T Suzuki sprocket besided increased cruising speed and decreased RPMs.

Assuming that the quality of the aftermarket is inferior to that of the OEM sprocket is a mistake. After having this thing on for 200 miles now, I can't imagine why Suzuki wouldn't make this sprocket standard for our bikes.

The decreased revs at cruising speed make for a much more pleasant ride. There is no longer a nervous feeling above 55mph. The bike settles and it much more capable of making long distance rides.

After riding quite a bit, I've noticed an overall decrease in 0-60 times, but it's negligable. The increase in every other aspect outweighs it anyhow.

[Jordan310]

Actually,

I spoke to a dealer and the parts guy and there is a 16 tooth sprocket that will fit the bike.
It is a bit thicker/sturdier, and the rubber piece does do some dampening.

Im sure the aftermarket part works fine, but Ill stick with the OEM.

In any case, I wonder what a front AND rear sprocket change would do..

[Water Warrior 2]

Changing both sprockets to achieve even lower RPM might be counter productive. The 250 only has so many horsepower to work with and you might actually make top gear useless. You wouldn't have the power to pull real tall gearing.

[Jordan310]

I wonder if that would be true with the big bore kit Im having put in it though ;)

[jonathan180iq]

Who makes a big bore kit for this bike?

[Water Warrior 2]

Like the sound of a big bore kit. Bumping up the displacement another 100 cc's or so would be a huge difference. The added displacement even in mild tune for reliability would likely allow for another tooth on the front sprocket and a couple less on the rear. Without going overboard this combo could be very nice for cruising the highways and give a longer, more powerful pull in every gear. But here is a less than great thought. Would the 250+ develope a vibration typical of larger thumpers ??

[Jordan310]

Well,

Obviously yes I would say that the virbration will increase quite a bit. The kit adds only about 80cc's more and yes, Im sure of the increased vibration.
Still - I highly doubt it would be bad at all.

I would love to have the bike geared for 1/4 mile quickness, and easy highway revs up to 90Mph.

[jonathan180iq]

I'm going to be skeptical of this big bore kit until I see it done.
I don't mean any offense to you, but I've seen more than a few 250cc bike riders make claims about big bore kits that don't exist and all types of other schenanegans.

[Jordan310]

Bro, look at the link in my other posts.
i ordered the parts, and they are readily available for this engine.

[Gadzooks Mike]

Did this mod take away too much power? Right now, I generally have to downshift from 5th to 4th to get up many hills. After the mod, does it still climb decent in 4th? It seems like there would be enough oomph in 4th to handle it, but thought I'd check before I ordered a sprocket.

[jonathan180iq]

Thanks for getting back on topic :2tup:

Without a problem. There isn't any power loss. The power has just been spread out over longer gears. If you get up into the top of the rev range in any gear it will still move.

I find that 4th is actually more useful. Normally, aroud the time that you would shift to 5th, say 45-50mph, you can hold out in 4th, eliminating the downshift scenario alltogether. I use the new 4th gear well into the 55mph range. It's capable of 60 without redline.

My initial reaction was a little over the top. Having spent more time on the bike, the change isn't mindblowing; it's utilitarian. I recommend this mod to anyone and I can't understand why Suzuki wouldn't use this as the standard gearing. However, if you're looking for blow-the-doors-off acceleration you're looking in the wrong place.

The 13% increase in gearing yields much more even riding, fewer gear shifts, increased fuel economy and, one would imagine, a longer engine life as a result of the decreased need for excessive revving.

Take care,
Jonathan

[jonathan180iq]

Like the sound of a big bore kit. Bumping up the displacement another 100 cc's or so would be a huge difference. The added displacement even in mild tune for reliability would likely allow for another tooth on the front sprocket and a couple less on the rear. Without going overboard this combo could be very nice for cruising the highways and give a longer, more powerful pull in every gear. But here is a less than great thought. Would the 250+ develope a vibration typical of larger thumpers ??

I think in this case clearance would be an issue. With the 16T sprocket, the chain is already pretty close to the engine block. Aside from that, I doubt that you could find a 17T sprocket.

[Gadzooks Mike]

Thanks for the info Johathan! I wasn't looking to blow away any doors, believe me. What I am looking at are some long trips this summer, possibly up to 1000 miles or so each running at 55-60mph, and didn't want to be running with high revs all day long. I'm sure the bike would take it, but I'm also pretty sure it would shorten the engine life considerably. This mod just sounded good, and I really appreciate how detailed the instructions are, too! I just ordered the sprocket, hope it shows up by this weekend. Thanks again!!

How do I lose this "Newby" tag? Heck, I've been here a long time, especially in dog years!

[Jordan310]

Im wondering if you saw that for the JIT sprockets, they sell the Universal Bushings that go with th 16 toother.
Currious to know if you checked that out.

[jonathan180iq]

How do I lose this "Newby" tag? Heck, I've been here a long time, especially in dog years!

Seems to depend on the number of posts. But I don't really know.

[Gadzooks Mike]

Hey, what can I say? I post quality, not quantity! Heh heh

[davidc83]

Actually, doing 55mph should not shorten the life. If you go to http://home.comcast.net/~pat1776/Alaska05/index.html (copy and paste into your browser), you can read the story of a guy who did 10,000 mile Alaskan road trip on a gz250 in 19 days. He still has the bike and now has close to 50,000 miles on the bike.

[Gadzooks Mike]

Yes, I believe his name is Pat, and I've read the story and chatted with him as well. If I stick with 55, I'd be fine, and I understand that. However, there are times....

[Jordan310]

I consistantly keep my 07, at about 65Mph.
I think this was good durring the break-in perriod, but I dont sense that the engine is overworking itself.

[Gadzooks Mike]

Well, in any case, I've already ordered the sprocket, and will install it when it arrives.

[Gadzooks Mike]

Hey, I'm not "Newby" anymore!!

Gosh, I miss the good old days.... heh heh

[jonathan180iq]

Hey, I'm not "Newby" anymore!!

Gosh, I miss the good old days.... heh heh

There you go. It must have passed over around 25 posts.

As I mentioned the sprocket change is no big deal. Having the maintenance manual is always a boost to one's confidence, I'd recommend it.

Have fun and post your results here so others will have a second opinion on the sprocket change.

Take care,
Jonathan

PS: I have a couple more detailed photos if you need any help. Feel free to PM me.

[Gadzooks Mike]

Got my "go fast" (sprocket) today in the mail. It took all of 30 minutes to do this mod, start to finish. My thanks again for the step-by-step instructions - they were perfect! Only had time to make a quick run through the neighborhood, then came back to check nuts and bolts again. Will give a better description of how it runs when I can get it out on the road, however - at first blush, it's nice! It's difficult for me to describe, but all I can say is that it seems to run "smoother" - I think that's because of the lower rpm's. It does make a definate difference, at least at low, neighborhood speeds.

Thanks again for the terrific job with the instructions!! :2tup:

[jonathan180iq]

Just wait until you get out on a nice country road and start plowing through some rolling hills around 55-60. The smile will last for days.

The neighborhood effect is much less than the difference on the open road.

I'm glad I could help.
Jonathan

[Jordan310]

55-60?

My bike does that stock.. :cry:

How about 75-80?

[Gadzooks Mike]

So did mine, Jordan, but that's not the point. To be able to run a 60mph and still have some play left in the throttle is nice. To be able to get up a hill in fourth at a decent speed without shaking myself off the bike will be nice, too.

Jonathan, I'm hoping to take a bit of a longer lunch hour today... heh heh

[Jordan310]

Gadz,

But wait. I never need 4th uphill unless the incline is super steep, and then running at 60 is nothing. The engine has quite a bit of rev left in it.
I never get any shaking at all. Once I hit 75Mph stock on this bike, it pushes hard to try to reach 79mph. at about 77-78 there is a little shake, but not much at all.

The only problem with 77-79Mph is the high revs, and nothing left when gunning it full throttle.
I think everyone's bike runs different, and It might have to do with the fact that I did the airbox removal, stock filter bolted directly to the carb, and rejet going on, but my bike seems happy at 65 for sure with quite a bit of oomph still left.

I'm wondering now that I ordered the 16 toother with rubber, what the deal will be.

[Gadzooks Mike]

Well, there you go. Your bike is much faster than my bike.

[jonathan180iq]

Gadz,

I'm wondering now that I ordered the 16 toother with rubber, what the deal will be.

you have a part number on that?

[jonathan180iq]

55-60?

My bike does that stock.. :cry:


As I stated before, this isn't a mod done for a massive increase in top speed. It lowers cruising revs throughout the power band and rpm range in all gears. I've also noticed an increase in my fuel economy of 4-MPG.

In the post that you are replying too, you misunderstood my point. I wasn't raving about the amazing power at 55-60mph, I was trying to infer that the largest impact of this new sprocket comes in that area, where most of us spend our time anyhow.

[Jordan310]

I usually end up averaging about 65 Minimum to 77Mph on the 4 lane freeways.
I really hope this mod adds some needed ease to reaching top end for the bike.

Im also wondering, .. does slack in the chain have much to do with the response of the bike in reaching its needed gears?
Will a decrease of slack improve the bikes oomph?

:??:

[jonathan180iq]

Im also wondering, .. does slack in the chain have much to do with the response of the bike in reaching its needed gears?
Will a decrease of slack improve the bikes oomph?

:??:

That's a big N-O. There is an optimal tension that your chain needs to be set to in order for the bike to function properly.
Too much slack and you'll notice a decrease in rideability. Too tight and you'll be putting too much tension on the chain and the drive components.

Loosening your chain will not give any boost to performance. Adjust your chain per the service manual and you'll be good to go.

Did you get a part number on that OEM 16 tooth sprocket yet?

[Jordan310]

K.

Ill look for that part number and post it when I have it.

[jonathan180iq]

Just for future reference, the stock gear ratio is: 2.73

The gear ratio with the new sprocket is: 2.56 (The same as the stock GS500)

(2.56-2.73) / 2.73 = 6.23% change is gear ratio

[Dirt_McGert]

Just ordered a JT 16-tooth front sprocket from BikeBandit.com

Hoping to get it installed in a week or so.

[Jordan310]

They are a great company.
I ordered a test sprocket to compare with the Suzu 16 tooth.

They also sent me a metal "bushing" for the sprocket. Im unsure what this ring does, or its application,. but it went along with the sprocket. Does anyone know what this is?

[jonathan180iq]

Whatever it is doesn't really matter for us, as we don't need it.

What's the part number on that Suzuki sprocket? Or at least a photo of it

[Jordan310]

Whatever it is doesn't really matter for us, as we don't need it. :tdown:

Thanks for the helpful advice. Look the part number up yourself. Its readily available from a knowledgeable mechanic or Suzu dealership.
For everyone else, Im sure this metal bushing has some application for the sprocket. I just am unsure as to how it fits into play.

[jonathan180iq]

That should read "Whatever it is, it doesn't really..."

sorry
I wasn't blowing you off

[Jordan310]

Im not sure.
Why would JT bundle them together unless it had a good use.
Could it be that the sprocket is for the dirtbike, or ... anyone?

[jonathan180iq]

My order didn't come with anything but a sprocket. no bushing. nothing else. Do you have a link for the part you ordered? I'll cross reference it.

[Jordan310]

5653551 JT Sprockets Bushing Qty: 1 Cross Shipped
$7.22 $6.50 1 - $0.00

[jonathan180iq]

That's your order number.

Either way, I can't find any mention of a bushing anywhere. Send me a link to what you are looking at.

I went to the JT Sprockets website and can't find 'em there. Also, according to their cross reference chart, there are no alternative sprockets in the world of motorcycling that fit the GZ, save the original version of this bike, the GN250. The sprocket for the GZ is the same part number as for the GN.

You can't even use the DR250S sprocket because of an extra large bulb on the area where you would have to bolt the sprocket on. This bulb wouldn't allow the bolt to seat on the GZ, meaning your chain and sprocket would come flying off.

[jonathan180iq]

Found it.

http://www.bikebandit.com/partsbandit/p ... Path~4.asp (http://www.bikebandit.com/partsbandit/product~pf_id~5653551~section_dept_id~1170244~terr ain_dept_id~1173059~cat_dept_id~2299779~product_de pt_id~2299779~mfr_name~JT+Sprockets~selection_Path ~4.asp)

This is just a universal sprocket. It's not necessary for our application. It's not specifically designed for the 16T sprocket or any other thing for that matter. I guess on some other bikes it might be needed. But the purchase of a certain sprocket would most likely prompt the purchase.

I put the sprocket on my bike and there was no point in the application where it could have been used. After several hundred miles of riding, there is also no flaw with it's operation.

Check this out.
http://en.wikipedia.org/wiki/Bushing

[Jordan310]

Weird.
I was wondering why they gave it to me for free, and then why they suggested it.
I know what a bushing is, just not a metal one like this.

Thanks for the info.
Now Im just currious as to know for what bike this IS used for.

[jrockrat]

Anybody have the 16 tooth and a tach that can tell me what RPM they run at 65-70 MPH?
Thanks

[jonathan180iq]

For that info to be even more useful, it would help to have the RPMs with and without the sprocket change.

[El_Shorto]

Guys, how long did it take for them to get the sprocket to you? I ordered mine over 2 weeks ago and selected the standard 3-5 day shipping, no dice. I also cant find a number on the website for customer support. Any ideas?

[Gadzooks Mike]

It took a couple of weeks to arrive.

[jonathan180iq]

I got mine in 6 days. .... Where did you order from?

[El_Shorto]

ordered it from the place linked here on the forum. I checked with them and they said its on a huge backorder. I think you started a trend!

[Easy Rider]

ordered it from the place linked here on the forum. I checked with them and they said its on a huge backorder. I think you started a trend!

Ordered mine through the dealer. Got it in 3 working days; got it on 2 days later.

:neener:

P.S. I've seen reports from about 15 people who have changed the sprocket. All liked the result; none reported any drawbacks HOWERVER, there is bound to be somebody out there somewhere that won't like the result: KEEP THE OLD SPROCKET JUST INCASE!

[jonathan180iq]

P.S. I've seen reports from about 15 people who have changed the sprocket. All liked the result; none reported any drawbacks HOWERVER, there is bound to be somebody out there somewhere that won't like the result: KEEP THE OLD SPROCKET JUST INCASE!

Good idea to have out there. I have mine, but for a different reason.
If you ever decide to sell your bike, you'll get more money in stock form with accessories on the side. Modifications actually lower the market value.

[Easy Rider]

If you ever decide to sell your bike, you'll get more money in stock form with accessories on the side. Modifications actually lower the market value.

In some exotic circumstances that may be true but, in general, used accessories depreciate a LOT faster than the bike itself. I agree, however, that radical mods probably reduce the used value but I don't do mods like that..............and I suspect that nobody is going to go to the trouble of reversing radical mods either.

At any rate, should I have to sell my bike (whatever it is), I'm damn sure not going to remove all the bolt-on and strap-on accessories (unless they fit MY new bike).

For me that certainly includes the new sprocket because I'd MUCH rather have potential buyers ride it that way than with the crappy stock setup.

[jonathan180iq]

For me that certainly includes the new sprocket because I'd MUCH rather have potential buyers ride it that way than with the crappy stock setup.

WORD! :2tup:

[Dirt_McGert]

Anyone have the torque specs for the front sprocket 30mm nut?

[Easy Rider]

Anyone have the torque specs for the front sprocket 30mm nut?

Make it TIGHT.
Gague by feel.
Lock the washer and it ain't goin anywhere!

[Sarris]

Manual page 3.7 under Engine says 90 n/m or 65 lb/ft.
:rawk:

[quint8]

The JT 16T Sprocket is on back order until 8/20, info is from JT Sprockets! :sad:

[xt477]

jt sprockets or bikebandit? I had one on order from bikebandit who told me the same thing. Was thinkning of trying to get one from MAWonline but if it's from JT then I will reorder from Bikebandit.

[quint8]

I checked with all the websites who carry the sprocket and all said 8/20. Then I called JT and was told that they had an order coming in and they would let me know when they were available. I'll let everyone know when I hear from them. :rawk:

[Quimrider]

I've been trying to order one since june!!! They keep canceling my order because it's on back order for too long!!! Bike bandit told me today "I am very sorry, but now our supplier is saying that they cannot get those sprockets anymore. I really do apologize for that" and " I am very sorry, but no one else makes any aftermarket sprockets for your model." when I asked if they had a 16T sprocket from any manufacurer for the GZ250.

[Easy Rider]

I've been trying to order one since june!!! They keep canceling my order because it's on back order for too long!!!

Have you visited or called around to dealers in your area?

If any of them handle "3rd party" parts, they might be able to get one pronto. When you add in shipping, the cost probably wouldn't be much different either.

I got mine in 3 days. :cool:

[Quimrider]

There's really only one dealer in Toledo and they pissed me off so I won't shop there, but there are a few within driving distance that I will check out.

[Stretch]

I have been back ordered on that sprocket for almost a month and a half! Every time I read a posting about how smooth it is I drool. If your sources are right, we may have more parts in the pipeline within the week.
:tup:
-Bob

[Quimrider]

FYI I don't know if it's been posted here or not but the JT part number is JTF434.16. I've googled this part number and found it for sale at various websites. I will try them if my local shop can't get it.
http://www.jtsprockets.com/52.0.html?&L=0&sel_uid=1581&p=

[Quimrider]

I gave up trying to order one online. I've been trying since June. I ordered one from my local shop for 18 bucks and it should be here by wednesday.

[Quimrider]

The local shop said it is on back order with the distributor until sometime in October! If anyone knows where that actually have these in stock let me know.

[Stretch]

BadBob started a new thread in the Mod's section stating that the JT 16T sprocket is discontinued and that Sprocket Specialists did have some. I did a little legwork on that and found out a bit more. Here is a copy of my reply in that thread for those of you who may be interested:

My Suzuki dealer's wholesalers couldn't find a 16T. I found the Sprocket Specialist's phone number on their website (www.sprocketspecialist.com (http://www.sprocketspecialist.com)) - 1-800-782-8200. They do have TWO left in stock, but they said they are getting more in next week. Their part number is: 528-16 Front Steel Sprocket (C/S)/Std/16 Teeth/For 520 Chain. Price: $21.99 + $6.26 S&H. They are currently out of chains (BadBob must have gotten the last one!). They don't stock the rear sprockets, but they cut them to order when you ask for one. The part number on the rear sprocket is #461 and the cost is $52.99 plus shipping.

I hope this helped. Thanks for the head's up BadBob!
-Bob
:tup:

[Quimrider]

correct url:
http://www.sprocketspecialists.com/

[Stretch]

:oops:
Darn those plurals!
-Bob

[Jaime]

I've installed mine today and it's better than expected. 1st gear is no more useless and 4th is quite useful in highway, getting up to 78 mph. I've reached the same top speed than before at the same road; 81 mph.

[Gadzooks Mike]

Jaime, maybe you can do better than I did trying to explain how different it is. All I can say is that it's a different bike and I don't ever want to go back to a 16T sprocket. Congrats!!

[davidc83]

Mike, do you mean you wouldnt go bact to the 15T or dont you like the 16T?

[Jaime]

I've understood "going back to 15T"... Anyway, I think that my English is a bit limited to express my feelings about a sprocket. :oops:

The bike is simply smoother and not less powerful, but keep in mind that I've recarburated it, giving more fuel and air.
Also, the three first gears of the GZ250 are so short that they can be extended without any problems, only getting advantages. On the other hand, the change in 4th and 5th gear final ratios could be critical in some of your bikes.

I'm posting the Suzuki OEM part number for the 16T here too, in case anyone needs it:

#27511-37200

[Jaime]

Gears, rpm and speeds of both sprockets. Based on the real ratios/speeds, not on the speedometer.

http://img.photobucket.com/albums/v248/hellcracker/16T.png

[jonathan180iq]

Again, nice work. I really appreciate this research that you are doing.

Now if we can just find a few more HP in this little bike, we'll be set.

It would really be nice to have a second cylinder...:)

[Gadzooks Mike]

But then you'd have a Rebel! Heh heh

[Jaime]

Next week I'll post a video reaching 90+ mph... Next week because I still don't get that high speed, but I'll reach it for sure. :cool:

[Badbob]

But then you'd have a Rebel! Heh heh

That wouldn't have to stop for gas every 100 miles.

[Water Warrior 2]

The rebel is also a slightly smaller( cramped) bike to sit on. The handle bar knee clearance in tight turns is almost non existant for longer legged folks. Still a fine bike that has brought many people into riding without scaring them silly with power and weight issues. Still doesn't look as good as a GZ.

[Gadzooks Mike]

The rebel is also a slightly smaller( cramped) bike to sit on. The handle bar knee clearance in tight turns is almost non existant for longer legged folks.

I agree with that. When I started looking for a bike, I was looking at the Rebel. As soon as I sat on one, I got up and went to look at the GZ, and haven't regretted it for an instant. As you say, they are fine bikes, though.

[jonathan180iq]

I think Honda remedied the Rebel with their Nighthawk. But, alas, no one rides Nighthawks.

[Badbob]

But, alas, no one rides Nighthawks.

I'd ride one if they made them with a disc brake. If I found one cheap enough I'd buy it anyway. I almost bought a NightRebel/RebelHawk hybrid last year. The seller wanted to much for it and would not come down off his price.

I've seen quite a few CB250s on the road. Way more than I have seen GZ250s. So somebody rides them.

[Gadzooks Mike]

I'm not sure I'd call the Nighthawk a remedy.

[Quimrider]

Finally after waiting nearly 3 months I got my 16 toot sprocket. I don't think this makes the bike feel completely different as others have said. Having said that it is definately worth it to go to the 16t sprocket. The 2 areas of improvement I see are:
1) first gear isn't useless anymore. I can actually complete a turn before shifting to 2nd.
2) top speed is about the same but the engine sounds less "angry." Frankly I'm surprised at the difference in sound as it is only turning a few hundred rpm less.

[Easy Rider]

1) first gear isn't useless anymore. I can actually complete a turn before shifting to 2nd.
2) top speed is about the same but the engine sounds less "angry." Frankly I'm surprised at the difference in sound as it is only turning a few hundred rpm less.

It's all a matter if perception, I guess.
The two things you mentioned are exactly the things that made me say it DOES feel like a different bike.

:roll:

[Badbob]

I got my new sprockets and chain Friday. I had hoped to get them installed but work and other things prevented that.

It migh be two or three weeks before I get to it. :sad:

[Stretch]

I had new tires put on (the old ones were far too worn to be safely ridden), a carb clean (horribly dirty), a new plug (burned far too lean), a slight tune and the new sprocket. Awesome improvement! Much more fun and better handling/speed. I wanted to do each item individually to get a feel for each change, but I ran out of time and patience.

My trip down memory lane? The gearing ratio of the 16T on the GZ250 is an almost exact match with the stock 1968 VW Bug four-speed I learned to drive on! First gear gets me through the intersection, second takes up right up to a 30 mile per hour zone and then begs for an upshift, just to lug unless I creep up to 35. Third gear is now my go-to gear for most arterials and on-ramps with fourth handling everything up to highway speeds (65 MPH now is not a problem and I even had it up to 70). Fifth, which didn't exist on the VW, is truly an overdrive now, if I upshift into fifth, any change of condition requires an immediate downshift to do anything about it.

:2tup:
I tell you, once I get all the of the stuff repaired on this bike that were allowed to degrade under the former owner, you will have to pry my butt off that tractor seat with a crowbar!

-Bob - a happy camper!

[Bud]

I want to do this mod. However, I am concerned about previous posts that said people had trouble getting the part. Anybody had this problem recently? What is the best source as of today? - Bikebandit? sprocketspecialist?

[Easy Rider]

I want to do this mod. However, I am concerned about previous posts that said people had trouble getting the part. Anybody had this problem recently? What is the best source as of today? - Bikebandit? sprocketspecialist?

A good question, since I don't think it's been discussed for at least 6 months.
I'd try a local Zuki dealer first.
After that, the best source is anybody who's got them! :)

[Quimrider]

I'm not sure if it's in this thread, but somewhere someone found the suzuki 16t sproket. It was for a different bike but fits the GZ250 just fine. If you can find the part # you can take that to just about any suzuki dealer and order it. The JT sproket I believe was discontinued. Let us know if you find one.

[jonathan180iq]

I think I remember Jaime mentioning a Suzuki part number for the 16T sprocket. IF you can find that post, then go for it.

Jordan310 once claimed of a Suzuki part number for the 16T sprocket but never backed it up. I assume that this is same thing.

Jaime's posts are trustworthy.

[5th_bike]

Hey Jonathan I like your Dutch 'Bike Path' Sign avatar - makes me feel at home :tup:

[jonathan180iq]

Where are you from?

[5th_bike]

Where are you from?
From The Kingdom of The Netherlands. Where many roads have a separate bike path, indicated by your avatar. You would like it there.
Highways and city streets usually don't have a bike path. Highways are no-no for bicycles. And in the city, the cagers know to keep a space for bikes. I failed my first car driving exam for passing a bike too close.

[jonathan180iq]

Wow. That's nice. I didn't realize we got so much international attention. Are you living in the States now?

[5th_bike]

Yes, actually my location "Maryland" is in the States.
I've been here long enough to get used to those roman empire era units "miles", "feet", "pounds" etc. that they still use here.

[jonathan180iq]

hahahaha
Yeah. I haven't quite figured out why we do that. Maybe because we are the new Rome? There is really no other reason for it.

[patrick_777]

Installed mine today. I haven't had a chance to take it more than around the neighborhood, but a few days without rain this week will give me time to ride and test it out.

Total install took about 45 minutes, give or take.

Like someone before, after I installed it, I had a little bit of chain noise from the sprocket, so I dabbed some chain lube between the teeth before I set the bike back down and it cleared it right up.

Also, after a thorough chain and sprocket inspection, I definitely need to clean and lube. That rear sprocket is nasty.

[jonathan180iq]

It'll stay that way too. Chain goo gets dirty really quickly.

I have a hell of a time trying to keep the rear wheel clean. There is just no room to manuver(sp?).

For refence, would you mind sharing where you got the sprocket?

[patrick_777]

http://www.bikebandit.com/product/A5270576
The specs appear to be wrong on that product page, and the picture is of a 14T sprocket, but that part number is the 16T. I counted them.

Shipping was fast. Ordered it on the 28th of May and received it on the 2nd of June.

[jonathan180iq]

Well that's good. They must not be discontinued afterall. That, or they bought the last ones they could find.

[patrick_777]

I just rode down to work and back (about 9 miles each way) to try out the new sprocket. Everything mentioned in this thread is just about right. This is a great mod if you don't plan on going over 60, but really want to work in the 40-50 range comfortably.

The bike accelerated through first quickly, but I could make it scream to 25 until I shifted to 2nd, but it wanted a change in gear around the 18-20 mark.

Second and Third were perfect gears for city roads and gave more play in the throttle than I ever thought possible.

The sprocket has virtually eliminated the fifth gear. Fourth would take me to 60 easily and 65 was near the top end. If I upshifted to fifth, the bike would rev down, and eventually the speed would drop to 60 and fall slowly. (Note: I was facing a 5-7mph headwind tho.)

The most comfortable gear I stayed in was third. I held with traffic at 40-45 in third and it had plenty of throttle left for more power if I needed it. The trick that this mod did for me was narrow down the throttle play I had. The bike wanted to bite every time I changed gears, or from a stop. It was almost like the friction zone was thinned out dramatically. It made me focus more on shifting smoothly though, since I didn't have to up and down shift as often on the streets.

To summarize: The sprocket really kills the top end on the bike. My suggestion, like others is, stick with the 15T if you do a whole lot of highway or higher-speed back roads. If you're commuting to work through city streets where the bike seldom needs 50+ mph, then the 16T sprocket will give you the gearing and throttle play you need to handle the traffic more comfortably and safely.

[patrick_777]

For those that care, I replaced the 16T sprocket with the old 15T and I have to say, I like it better. The responsiveness isn't as twitchy, and it gives me the high-end speed I want. Since it's not a big deal to swap them around, I figure I'll try the 16 again in the future, but for now -- I think the 15 suits my needs better.

[Easy Rider]

I think the 15 suits my needs better.

And in the end, that's all that matters! :tup:

(I can't imagine going back.)

[Jpsalvador]

Can you clarify more on the chain tightening i have about 2-3" of play ... bad i know but i need help any answers?????

Jp

[Badbob]

Can you clarify more on the chain tightening i have about 2-3" of play ... bad i know but i need help any answers?????

Jp

The manual tells you how to do this.

[Easy Rider]

Can you clarify more on the chain tightening i have about 2-3" of play ... bad i know but i need help any answers?????

Jp

Bad to the point of being dangerous. If you don't have a users manual, you NEED to get one.
I believe there is one posted here......or a link to one.

[jonathan180iq]

You can get a downloadable/printable service manual in the very first post of the general maintenance section.

As for asjusting your chain, it's pretty simple. If you swapper out your rear sprocket you should know how to loosen the rear axel and the chain adjusting bolts. Just do one side at a time and tighten those bolts up. As they tighten, the rear sprocket will be pulled back and the chain with adjust itself.

[JWR]

Just to revive this old thread.

I took a 100 mile ride today with the 16 tooth sprocket.

Going south into a 10+ mile per hour headwind, I could pull it in 5th.
Headwind plus a hill I could not maintain. 60+.

The bike is really smooth between 45--65 in 5th.
Coming back with the tailwind was very smooth at 65 to 70.

Average throttle cruising is just over half at 65 mph.

I think the wind and road are the limiting factors for this gearing.

Overall I am very happy with this setup.
http://www.postimage.org/gxFOlLr.jpg (http://www.postimage.org/image.php?v=gxFOlLr)

[mr. softie]

I just installed a 16 tooth today and will try it out tomorrow.

[JWR]

The weather map says 67 today.

That part is fine but 5 to 15 mph winds.

I will have to find a tailwind.

Have fun.

Jerry

[Easy Rider]

I think the wind and road are the limiting factors for this gearing.

Overall I am very happy with this setup.


:plus1:

AND

:plus1:

The GZ looks right at home with it's bigger brothers!

[JWR]

Hey Easy Rider,

I think my bike and yours must be very close.

From my short ride, it seemed that I had to back off the throttle, more than I actually gave it fuel.

I really believed my GZ would pull the 16 tooth anyway that I wanted. I was wrong.
I did not realize just how tall this was.

Just a very different riding approach to maintain desired speed.

Best shift points
1st....20
2nd...30
4th....40
5th....50


MAX SPEED
1st....25
2nd...45
3rd....60
4th....70+
5th....??????

[Easy Rider]

From my short ride, it seemed that I had to back off the throttle, more than I actually gave it fuel.


OK, your gonna have to explain that a bit; you lost me completely.

From your speed chart, though, if you are "normally" doing 60 in 3rd and 70 in 4th, you are working the engine WAY too hard.......to achieve a reasonably long engine life, that is.
We have had a couple of riders on here that worked the engine WFO all the time and the engine was shot around 20K miles. Those speeds are OK once in a while under difficult conditions but not ALL the time.

There is no need to wind it out that much, under normal conditions, as it WILL pull 60-65 easily in 5th (if you get it up to about 55 in 4th) and will do 70 on the flat but it takes a while. If you wanted something that was FAST, you got the wrong bike and changing out the sprocket might be a mistake for you.

With the 16T you get more range and better use of the torque in the lower gears at the expense of the top end, which becomes HP limited as you just can't get the revs. up enough.

Your previous post indicated that you were happy with the new setup. Have you changed your mind ??

[JWR]

The speed chart was to give folks that don't have the 16 t an idea of possible top speeds.
I understand perfectly how the bike works with the new gear.

As far as backing off the throttle.....you have more throttle than the bike can use.
I roll on the throttle, then just back it off until the bike is just pulling, then add a little more throttle..
NOT just WOT.


Jerry

[Easy Rider]

As far as backing off the throttle.....you have more throttle than the bike can use.


Got it. Very true until you get the rev's up.
Is that "new" with the 16T or just worse?
I suspect it also did that some when stock but don't really remember.

[JWR]

Is that "new" with the 16T or just worse?

With the 15t, it never quit pulling.
As you well know, completely different riding style.

[Canuck]

what do you guys mean by "pulling"

overall horsepower?

[Easy Rider]

what do you guys mean by "pulling"

overall horsepower?

Yes. In top gear, under "normal" conditions, with the stock gearing, the engine will pretty much keep going faster the more you open the throttle all the way to the end....or very near the end.
With the higher gearing, in top gear you run out of HP somewhere around 1/2 to 3/4 throttle and additional throttle produces......nothing in additional speed. In truth you are gaining a tiny bit under most conditions but past a certain point the speed increase is VERY slow.

This disadvantage is offset by being able to stay in the lower gears longer (to a higher speed) because you are not HP limited there. Cruising is also more comfortable at the slightly slower engine speed........as long as you are content cruising at 65 mph or less.

[Canuck]

ahhh Perfect...

I understand the 16tooth fully now..

I totally forgot the gz could pull til the end with a 15t...its been awhile since i had it on


Made a few highway trips and wondered about another bike because of it but am always reminded when i re-read a post on here of why I chose to do it and what the conclusion is...

A bike that cant reach its highest speed potential which is much higher then posted speedlimits while also reducing the adverse effects of riding this sweet little bike hard...

in the end Gas is saved. and perhaps alot of the engine components due to the restrictions the 16tooth's gearing creates for the engines end power.

Pretty cool stuff.

[northern_ninja]

Just a quick question regarding the 16t sprocket, does anyone know if it'd fit inplace of the 15t sprocket on the 125? It seems there's no info on the 125, sofar I have had nothing but good coversations on here so you must be a real bunch of bikers, instead of other sites where they're just "talking the talk"

[Easy Rider]

Just a quick question regarding the 16t sprocket, does anyone know if it'd fit inplace of the 15t sprocket on the 125?

My guess is yes but my advice is: Don't do it.

The 250 is on the verge of being overloaded with the higher gearing.
My guess is that 125 would not like it at all.

On the 250, the cover comes off the front sprocket with just 2 or 3 bolts. It's really easy to take a look and see how much space there is.

If you DO decide to experiment with the sprockets, count teeth on the original first. You may not have a 15 to start with.

[kleinboy]

where can i purchase a 16t sprocket online?

[adrianinflorida]

Here you go:

http://www.bikebandit.com/product/17866 ... 7&t=1&td=1 (http://www.bikebandit.com/product/17866?mg=3997&t=1&td=1)

[David Bo]

I bought one and hated it... Want me to send it to you?

I bought one and hated it... Want me to send it to you?

Can you expand a bit on why you hated it? You're one of the few I've heard say this. I'm struggling with whether or not to do this mod - have heard plenty from those who like it and would love to hear your side.

Thanks,

Keith

[Quimrider]

I'm struggling with whether or not to do this mod - have heard plenty from those who like it and would love to hear your side.

Thanks,

Keith

Keith It spreads the gears out a little which many like for in town driving. The negative side of the 16 t sprocket is you sacrifice 5-10 mph off your top speed because the engine runs out of power before it can wind up. If you do much driving at 60+mph you might not like it. Then again if you do much 60+ you might be happier with a different bike. It's only 15-20 bucks and a half hour to install. Try it see if you like it.

[David Bo]

Keith, the reason I did not like the 16 tooth sprocket over the 15 tooth had to do with the lack of that black rubber ring. I looked everywhere to see if anyone supplied the 16 tooth sprocket with that ring but nobody does. Without that ring, I found my bike to be noisy at lower speeds. The rubber acts as a silencer when the chain comes in contact with the teeth of the front sprocket. It wasn't "terrible" but you could definitely hear it (click-click-click-click-click). You also can feel the engine working a little bit harder to get you going initally. You might need to make sure your throttle is turned just a bit more when you release the clutch. I had mine on for about a week and then I finally decided that (for me) the 15 tooth was better. I did the switch-back and I now use the 16 tooth sprocket as a paper weight on my desk. You see, not all was lost! If anyone wants it, give me your address... It only weighs about a pound, I can mail it to you. - David Bo

[Easy Rider]

It wasn't "terrible" but you could definitely hear it (click-click-click-click-click).

Well that's a new one. You must have REALLY good ears if you can hear that over the sound of the engine. :)

To each his own, I guess.
Perception is an interesting thing.

FWIW, that rubber ring is not there as a sound buffer but to minimize the jerk when the chain goes from loose to tight (and vice-versa) .......in deceleration and shifting mostly. There is another rubber piece inside the rear hub that also helps.

Being able to hear the chain go around the sprocket(s) is most often a sign of improper slack or not enough lube or both.

Last but not least, the "pulling harder to start out" kind of IS the whole point. Being able to complete a turn from a stop without shifting out of 1st in the middle is nice. The higher gearing makes better use of the low end torque that is inherent with a thumper. But, to be fair, a lot of that benefit is psychological too. If it doesn't bother you to have the engine screaming before you shift, then there isn't much point to even try the 16T. It did bother me.......and a lot of other folks too apparently.

Nobody here has ever claimed (I think) that the 16T is for everybody. In addition to the "extra noise" mentioned above, if your bike often carries a heavy load, spends a lot of time on Interstates (above 60 mph) or there are a lot of hills or high winds where you ride most, then it is probably NOT for you. I guess now we can add sensitive ears to the list! :biggrin:

EDIT: Just had another thought. How old was your chain when you tried the new sprocket? The noise you heard can also be a sign of a "wear mismatch" between the sprocket and chain. In this case, it could be a worn (stretched) chain with a new sprocket. Just a thought.

[David Bo]

The chain was and still is the original one. I have a 2001 model with about 3000 miles on it. I looked very closely to the rubber portion of the front sprocket and could see where the wider (outside) parts of the chain contacts it. I was under the impression that it was put there for some sound dampening benefits. -David Bo

[Easy Rider]

The chain was and still is the original one. I have a 2001 model with about 3000 miles on it.

I'd be getting a little nervous with a chain that is ~ 8 years old but .........

If the sound went away with the old sprocket back on
AND
Your rear axle is not near the back of the adjustment marks
AND
You don't notice any jerkiness or popping from the chain when the rear is turned slowly
AND
You don't notice any RED goop around the rollers (I think the "sealed" lube is red)
THEN you probably are OK on the chain and sprockets for a while yet.
It should be good for at least 10K if it was properly maintained. If it was neglected, then who knows.

No doubt that the new sprocket fit slightly different some how but I quite assure you that the rubber core on the front sprocket is NOT there to supress chain noise.

[DBD]

David Bo, if you still have the 16T sprocket, and are willing to send it, I'd like to give it a try.

Dan

[tommygun]

I had a similar noise with my chain and it is just over a year old. A little WD-40 to clean it up and then grease and noise is gone.

[tommygun]

Keith,
Keep in mind that the 16t + rolling hills = lots of people on your back! I switched back to the 15t due to the lack of power on hills (I have lots of hills in my commute).

[DBD]

I find that on most hills I want to be somewhere between 4th and 5th. It's too wound out in 4th and laboring in 5th. I was thinking that the 16T might make 4th just right for long uphills.

Dan

Keith,
Keep in mind that the 16t + rolling hills = lots of people on your back! I switched back to the 15t due to the lack of power on hills (I have lots of hills in my commute).

[Easy Rider]

I find that on most hills I want to be somewhere between 4th and 5th. It's too wound out in 4th and laboring in 5th. I was thinking that the 16T might make 4th just right for long uphills.

That's exactly what I thought when I had a 16T.....including a round trip through the Smokies.
I didn't ride it stock long enough to have a good feel for what it did on hills......'cause we don't have many around these parts. :)

Part of the problem, I believe, is people who are used to cages that never go over 3K RPM.....and are afraid of winding the little 250 out a bit.

[gripped]

just put the 16tooth on the tu250x. it was an easy process, i didn't need to put it on stands either. took about 30 minutes. rode about 30+ miles around the city on it tonight including 80mph on I-5 - with wifey as passenger. no problems whatsoever.

what a great difference. i believe that the swap makes the bike a much more "capable" bike and puts a broader range on the gears overall. less shifting down the road and a much more tolerable rpm at all speeds. I (and my wife) are not heavy ppl by any means...total weight being around 245lbs. max recommended weight for the tu is 355.

awesome. :rawk:

[Water Warrior 2]

Interesting results. Usually the GZ will sacrifice a little speed for lesser RPM with the sprocket change. Maybe the FI makes a difference.

[blaine]

Got my sproket from dealer in 3 days

[alantf]

Got my sproket from dealer in 3 days

Wish I could get parts that quickly. My speedo cable snapped a month ago, so I ordered one straight away, from the local bike shop. It arrived last thursday! :cry:

[primal]

I don't know if it's been mentioned in this thread already, but you should NEVER use a torque wrench to loosen a nut! Use a breaker bar, or even a large crescent wrench (which is what I used to change my Marauder's front sprocket), but NEVER a precision instrument like a torque wrench!

[Atlus]

Hey guys, after reading this tutorial I was inspired to try this mod.

Unfortunately I'm stuck! I can't seem to get the 16 tooth sprocket properly hooked into the chain to mount. I don't know if bike bandit sent me the wrong piece or if I'm doing something wrong, but no matter how much I've massaged the chain and sprocket I cant get it back onto the bike.

I noticed that the teeth on the new sprocket don't quite seem deep enough, as the chain isn't fitting/gripping fully. Is that to be expected or do I have a bad part? Thanks in advance!!

[JWR]

I loosen the back adjusters and axle nut.
Then I push the chain down with my foot, to get the back tire up as far as I can.
Pull off the 15t and put the 16t in as high as it will go on the chain.
This should give you enough slack at the bottom of the chain to pull with the sprocket enough to slip it on the the splines.

The teeth should look the same as the old sprocket.

Hope this helps.

[Atlus]

The teeth do look the same but the chain doesnt sit nearly as snuggly as the previous sprocket, did any of you encounter that problem as well? Im just worried since the stock 15 tooth was a perfect snug fit while the JT 16 tooth seems to have to short a pitch...

[Atlus]

I also noticed in the screen shot that the JT sprocket says "JTF434" while the one I received says "JTF520" could that be the problem?
http://s1.postimage.org/gN0mr-5e8c5d3bbd3cc10d28ebd93717907d4f.jpg

[JWR]

Wrong part.

That is for a 525 chain not a 520 chain.
If the roller length is 1/4" then its a 520. If roller length is 3/16" then its a 525.
So the sprocket is just a little thinner???

[Atlus]

Wrong part.

That is for a 525 chain not a 520 chain.
If the roller length is 1/4" then its a 520. If roller length is 3/16" then its a 525.
So the sprocket is just a little thinner???
Ahhh crap! I was so excited too!! Yea, the sprocket just doesnt sit completely on the chain unfortunately.

Dang, okay sorry to sound like a complete newb, so is there a part that will fit my current chain or do I need to get a new chain? If so, will a new chain fit both the new front and the old rear sprocket?
I followed bikebandits step by step aftermarket catalog to get the sprocket I currently have so Im not sure where I made a wrong turn :cry:

[Easy Rider]

Dang, okay sorry to sound like a complete newb, so is there a part that will fit my current chain or do I need to get a new chain? If so, will a new chain fit both the new front and the old rear sprocket?

There is an OEM (Suzuki) part that will fit. The number is posted on here in a couple of places, I think. I got mine, 3rd party, though my dealer.....for about $18, IIRC.

Whether or not you need a new chain and rear sprocket depends on the mileage and condition of the chain. If you get the right new sprocket, nothing else HAS to be changed......if the other parts are in good condition.

Do a little searching on here. What you need should pop right up.

[JWR]

Wrong part.

That is for a 525 chain not a 520 chain.
If the roller length is 1/4" then its a 520. If roller length is 3/16" then its a 525.
So the sprocket is just a little thinner???
Ahhh crap! :cry:


JTF434 is the part that will work. You had it right the first time.

It that is what you ordered, then they sent you the wrong part...

You name of the chain that you have on the bike is a 520.

You just need the right sprocket...

[Atlus]

Thanks so much for the info and quick responses! I contacted Bike Bandit and they indeed shipped me the wrong part! They're sending me a replacement no charge and no complications
:2tup:

[JWR]

Good deal.

[Atlus]

Okay I swear Im cursed with this dang mod. Today's the first truly beautiful day of spring here so I got ambitious and decided to pop in the new sprocket (no problem, right?)

Well, so far I've done everything according to the step by step but now am completely stumped. After loosening the rear axle bolts and fiddling with the chain tension screws, Ive only managed to tighten the chain tension and move the entire rear wheel further back.

How on earth do I get that sucker to scoot forward and loosen the chain? Thanks in advance guys, bahaha Im hopeless

[JWR]

I loosen the back adjusters and axle nut.
Then I push the chain down with my foot, to get the back tire up as far as I can.
Pull off the 15t and put the 16t in as high as it will go on the chain.
This should give you enough slack at the bottom of the chain to pull with the sprocket enough to slip it on the the splines.

The teeth should look the same as the old sprocket.

Hope this helps.

Changed many times using these steps.
The adjusters must have enough slack to enable the tire to move forward.

[Easy Rider]

and fiddling with the chain tension screws, Ive only managed to tighten the chain tension and move the entire rear wheel further back.

The obvious (smart assed) answer is: You fiddled the tension screws the wrong way.......which is right but not very helpful when you have a mental block as to how it works.

Hopefully after a short break, you will go back to it and see the obvious problem and move right along. If not, someone who still has a GZ will have to help. If I try from memory, I will probably confuse matters worse.

[blaine]

and fiddling with the chain tension screws, Ive only managed to tighten the chain tension and move the entire rear wheel further back.

The obvious (smart assed) answer is: You fiddled the tension screws the wrong way.......which is right but not very helpful when you have a mental block as to how it works.

Hopefully after a short break, you will go back to it and see the obvious problem and move right along. If not, someone who still has a GZ will have to help. If I try from memory, I will probably confuse matters worse.
YOu need to turn adjusters to the "LEFT" to loosen the chain,turn "RIGHT" to tighten.

[BillInGA]

Once you have turned the chain tensioning bolts to the left (counter clockwise) you will have to manually move / push the rear wheel forward to gain slack in the chain.

Also, put the sprocket on the chain before trying fit it back on the shaft.

[Water Warrior 2]

Everyone is missing the key factor. After turning the adjusters counter clockwise the tire will need a good swift kick to move it forward. Then you will have lots of slack and can proceed to tighten the chain properly. Been there done that.

[Atlus]

Everyone is missing the key factor. After turning the adjusters counter clockwise the tire will need a good swift kick to move it forward. Then you will have lots of slack and can proceed to tighten the chain properly. Been there done that.
Baha! That's what I was looking for! After a good kick forward my new sprocket is installed and ready to go. I look forward to testing it tomorrow. Haha when in doubt, kick it.

Thanks everybody for the responses, lord knows I learned everything about my bike thanks to these forums and community. :2tup:

[blaine]

Everyone is missing the key factor. After turning the adjusters counter clockwise the tire will need a good swift kick to move it forward. Then you will have lots of slack and can proceed to tighten the chain properly. Been there done that.
Baha! That's what I was looking for! After a good kick forward my new sprocket is installed and ready to go. I look forward to testing it tomorrow. Haha when in doubt, kick it.

Thanks everybody for the responses, lord knows I learned everything about my bike thanks to these forums and community. :2tup:
Good luck,hope you like the 16t sprocket!

:rawk: :rawk:

[Atlus]

Just took it out for a spin today, not only was it absolutely gorgeous out but my god did that sprocket make a difference! I tried it out on side streets, freeway, and hills and loved every bit of it. As a a pretty lite guy (around 140) it's a world of improvement. Thanks everybody for the help!

[blaine]

Just took it out for a spin today, not only was it absolutely gorgeous out but my god did that sprocket make a difference! I tried it out on side streets, freeway, and hills and loved every bit of it. As a a pretty lite guy (around 140) it's a world of improvement. Thanks everybody for the help!
That was my impression to.I weight about the same as you do.Glad you like it!

[Easy Rider]

loved every bit of it.

Yea !!!
But then we KNEW you would. :biggrin:

You likely will find that it limits your top speed and hill climbing ability a bit but I found that to be an acceptable trade-off.

[EddieSC]

Awesome. I've been looking to get a bit more out of my bike (Totally stock at the moment) and I think this may be the first thing I try.

[blaine]

welcome to the fourm.try the 16t,not a big deal to change back if you don't like it.

[brucea]

I bought two sockets from http://www.cheapcycleparts.com

They always have reasonable prices and fast service.

They were showing two 16 tooth sockets available, and I was not sure which one to get, so I bought one of each.

When they arrived, they are the same socket, just from different suppliers.

So, if you order from that site, just buy the less expensive one.

Your installation guide was awesome, and I did it myself in less than 40 minutes.

[nautec]

I did mine pretty quick on Friday and finally got to ride it today. I really do like it since it feels a lot more "calm" at 55-60 mph. One thing I noticed is there is a fast winding noise from the bike. Kinda sounds like a fast spinning metal wheel. I guess it is from not having those rubber rings on both sides of the sprocket. Bought mine from BikeBandit.com for $22 and came in pretty quick. Had to go to Sears to get a 30mm socket.

[blaine]

The noise you are hearing is the chain mating to the new sprocket and will disappear in a few miles. :rawk: :2tup:

[Easy Rider]

The noise you are hearing is the chain mating to the new sprocket and will disappear in a few miles. :rawk: :2tup:

Most likely that Blaine is absolutely right but......just to be sure, I think I'd take the front sprocket cover off one more time and make sure that everything is lined up properly.

If you didn't get the new sprocket all the way on (if that is even possible), it might be scraping the side of the chain or rubbing on the cover.

Highly unlikely, I think, but I wouldn't want to take the chance.

Having the chain adjusted too tight might make it noisy too. You did re-check for proper slack after hooking it all back up......right ??

[nautec]

I readjusted the windshield and I think that is causing a lot of noise I noticed. I am going to return the windshield back to the original position and see how it goes. It is possible that the chain is a lot snugger after I installed the sprocket so I might try loosening it just a bit.

[alantf]

It is possible that the chain is a lot snugger after I installed the sprocket

This suggests that you did not check the chain tension after doing the job. O_o Not a good thing . :tdown: :)

[Easy Rider]

It is possible that the chain is a lot snugger after I installed the sprocket so I might try loosening it just a bit.

Not only possible but highly likely.......IF you didn't loosen the rear axle during the sprocket install. The extra tooth will automatically make it tighter.

[nautec]

I did measure it. Before the sprocket change, the chain gave around 13mm. After I put it on, it will only give around 5mm and not any more. So it was snugger than original. I'm fairly confident that all the noise is really coming from my improperly placed windshield. That's what I think all the noise is really coming from with my full face helmet on. This noise only happens above 45 mph.

[Easy Rider]

After I put it on, it will only give around 5mm and not any more.

That's what I think all the noise is really coming from with my full face helmet on. This noise only happens above 45 mph.

OK, whole different ball game then BUT....5 "MM" slack in the chain amounts to about none at all.
I don't think that's within spec. even. Did you turn the back wheel to see if that was the tightest point ??

You can prove it once and for all by riding just once, out of traffic, with the helmet OFF.
It is usually pretty easy to tell the difference between wind noise and chain noise.
I think it's likely that your chain is too tight; noise or no.

[Water Warrior 2]

Ouch, 5 mm is way too snug. Your bike is in peril. Fix it or it will cost you.

[cayuse]

Personally, I think 5mm is very snug. Really not 'slack'. But you know what? That's what Suzuki says is the allowable minimum. Check p52 of the manual. :roll:

[blaine]

Personally, I think 5mm is very snug. Really not 'slack'. But you know what? That's what Suzuki says is the allowable minimum. Check p52 of the manual. :roll:

You are right,BUT--The chain would be much tighter than that when you are on the bike,or rebounding off bumps,or not at the tightest point of the chain.Also the chain had to be way out of adjustment to ever get the 16t sprocket on without loosing the rear wheel,also not good.Some serious maintenance needs to be followed before someone gets hurt.

:skull: :)

Don't mean to rant,but I am a stickler for maintenance.

:) :2tup:

[aboes81]

Hello, I recently got the 16T sprocket and when I went install it I noticed the missing rubber gaskets of the OEM one. The problem is that the nut (30mm one) that secures the sprocket doesn't seem to be able to secure the sprocket because it's thinner. Am I missing something?

[Easy Rider]

Am I missing something?

Probably not. You may need a shorter bolt......or an added washer, which I really wouldn't recommend, long term.

[blaine]

Hello, I recently got the 16T sprocket and when I went install it I noticed the missing rubber gaskets of the OEM one. The problem is that the nut (30mm one) that secures the sprocket doesn't seem to be able to secure the sprocket because it's thinner. Am I missing something?


The sprocket should slide on to the splines snugly even with out the nut.Make sure you have it on the correct way,than the lock washer.The new sprocket is a little thinner without the rubber
hub,It will still tighten.

:cool: :2tup:

[aboes81]

It tightened fine. I got it on and took it for a ride. The new sprocket makes a very noticeable difference. My favorite part is how much smoother the top end is. I can cruise at 65-70 comfortably whereas before the vibrations for the engine made me uncomfortable.

The only downside is that I always have a goofy grin on my face.

[Easy Rider]

It tightened fine.

So......if it tightened on the sprocket solidly.....then what was point of the original question ???

"The problem is that the nut (30mm one) that secures the sprocket doesn't seem to be able to secure the sprocket because it's thinner."

I'm confused.....but that's not unusual. :roll:

[nautec]

Just an update on my sprocket experience. I have noticed a gas mileage increase in my everyday commute. Went from 67 mpg average to 73 mpg average. Cool beans!

[Water Warrior 2]

The rubber gasket on the OEM sprocket is usually there to control noise but I doubt there is a difference in real world riding. I read some where that all Japanese bikes use OEM sprockets made by Sunstar. This could be their way of signifying OEM from aftermarket supplied sprockets.

[Easy Rider]

The rubber gasket on the OEM sprocket is usually there to control noise

I think it also functions as a "shock absorber" for the chain......along with the rubber parts behind the rear sprocket.

[Water Warrior 2]

[quote="Water Warrior":2tbqkcld]The rubber gasket on the OEM sprocket is usually there to control noise

I think it also functions as a "shock absorber" for the chain......along with the rubber parts behind the rear sprocket.[/quote:2tbqkcld]
Absolutely correct Easy. I failed to remember that part. My Vstrom (IIRC) did not have rubber on the front sprocket as OEM but the rear does of course have rubber shock absorbers in the hub. At 46,000 kms the rears were in fine shape and still snug in their beds which tells me I don't really abuse the drive train too much.

[Purpledrank]

911! I need help quick please! I'm changing my sprocket but the new one wont fit. Its the correct sprocket, but when I go to put it on, the chain gets fully extended before I can get the sprocket on, as if the chain is too short. I loosened the rear axle nut, and I have full slack. The problem only occurs when I go to put the sprocket on. Immediate help would be appreciated. :D

[ncff07]

hmmm isnt there adjusting nuts on the ends of the swing arm to loosen or tighten the chain too? like take the cotter pin out of the axle nut then loosen that then turn the nuts on the swingarm(both sides) for more slack? or something? :poke2: did you consult the owners manual on how to adjust the chain? itll give you instructions.

[Water Warrior 2]

Sounds like an easy fix. Once the rear axle is loosened you have to turn the axle adjusters counter clock wise. There is one on each side of the swing arm by the axle. The axle adjusters will go all loose and a bit floppy but don't worry. Now just kick the tire to move it forward on the swing arm. Install sprocket and chain. Adjust the chain for proper slack using the adjusters. Remember a little bit of adjustment (clockwise)will take up a lot of slack so take your time. Try 1/4 turn at a time per side to get familiar with the way things work. It may seem intimidating first time round but is far easier 2nd time round. Yup we have all been there done that and survived with a little help from our friends.
Now some one else can wade in and add stuff I forgot to mention. :biggrin:

[Purpledrank]

Thanks guys! I got it on, turned it on, and rode it. Honestly, I dont feel much of a difference. I'm still shifting from 1st to 2nd at around 10-15 mph. The sound of the motor seems about the same. Did I do something wrong?

[blaine]

Thanks guys! I got it on, turned it on, and rode it. Honestly, I dont feel much of a difference. I'm still shifting from 1st to 2nd at around 10-15 mph. The sound of the motor seems about the same. Did I do something wrong?

You did get a 16t sprocket,not another 15t by accident. :??: :cry:

[Easy Rider]

You did get a 16t sprocket,not another 15t by accident. :??: :cry:

That or.......if he really was not shifting out of 1st until 15 mph......he can't be all that sensitive to the sound and feel of the engine in the first place. Seems like I remember it was SCREAMING at 15 in 1st. :shocked:

[alantf]

..........Or did it have a 16 tooth to start with?........(did you count the teeth on the old one?)..........

[Purpledrank]

its definitely 16t. I counted it when i bought it. I'll be riding to work soon, so I'll post any updates if anything feels wrong/right.

[3-D Video]

..........Or did it have a 16 tooth to start with?........(did you count the teeth on the old one?)..........
its definitely 16t. I counted it when i bought it.
I think what Alan meant to say was, did you count the teeth on the old... sprocket?

[Purpledrank]

..........Or did it have a 16 tooth to start with?........(did you count the teeth on the old one?)..........
its definitely 16t. I counted it when i bought it.
I think what Alan meant to say was, did you count the teeth on the old... sprocket?

I didn't check the old one, but side by side, the new one was a bit bigger.

So I rode to work today and noticed more of a difference, mainly in the higher gears (4th and 5th). It definitely sounds less violent as I approach 50 mph. I haven't attempted highway speeds yet. Also, now my brake pedal makes noise when I apply it about halfway...normal? or did I do something wrong?

[blaine]

Did you readjust the rear brake after putting on the new sprocket? The bigger sproket puts the rear wheel further forward requiring a small adjustment of the brake at the rear wheel.

:cool: :roll:

[Easy Rider]

The bigger sproket puts the rear wheel further forward requiring a small adjustment of the brake at the rear wheel.

True but my first impression from reading that is:
If you have enough travel in the rear brake pedal that you can tell "half way", then there probably is WAY too much travel.

It certainly would be worth while to get the back wheel off the ground and re-check the adjustment......including the pedal height adjustment up at the pedal........and finally the brake light switch.

While you're at it, recheck the chain slack and alignment. If you didn't have the back wheel all the way off, it's unlikely that there is anything drastically wrong.

[edit] Maybe a clarification is needed. It's somewhat unusual for a rider to say his brake PEDAL makes noise. Where does it sound like the noise is coming from ???

[Purpledrank]

Sorry, I dont mean the pedal, I mean the rear brake in general. It only makes noise while moving, so Im assuming it has to do with alignment of either the rear wheel or the brake. I DID notice last night, however, that the right side of the rear wheel was off by two notches compared to the left side. (Using the markings on the black bar) Could this have something to do with it?

edit: chainslack is fine, its set to what it always was. I think its more a matter of alignment, I just dont know whether its wheel alignment or brake alignment. :??:

[JWR]

Im assuming it has to do with alignment of either the rear wheel or the brake. I DID notice last night, however, that the right side of the rear wheel was off by two notches compared to the left side. (Using the markings on the black bar) Could this have something to do with it?

edit: chainslack is fine, its set to what it always was. I think its more a matter of alignment, I just dont know whether its wheel alignment or brake alignment. :??:


The side marks are there to line up the tire and wheel.
They must be equal the keep the tire and wheel straight.

[Water Warrior 2]

Time to start over a little bit. The notches will align the wheel as mentioned. If the wheel is not aligned the chain and sprockets will not be aligned and severe wear of parts will occur as well as a chance of the chain actually cllimbing off a sprocket. With the wheel aligned and chain slack correctly measured the next step is brake adjustment and brake light adjustment. The brake pedal should not go half way down as Easy cautioned earlier. 1 inch to 1.5 inches is a better distance of travel before braking occurs. You don't want to be extending your foot way down when it is not necessary. Also adjust the brake light to come on just a little bit before actual braking occurs. The owners manual actually has measurements for the pedal but most folks fudge them a little for personal comfort and travel. The pedal height can be adjusted first and then the brake rod to the rear wheel is adjusted to apply the brakes. This is done with a wing nut on the rear threaded portion of the rod. This in turn will move the lever on the brake drum to apply the braking forces.
Take your time and play with the brake peal with your hands. Sit beside the bike, move the pedal and watch which parts are moving and look for any adjustment fittings. Look at where the brake light switch is mounted and see how it works and determine how to adjust it when you are ready.
Hope I haven't thoroughly confused you. A bit jumbled but others can help straighten out my wording. I am sometimes accused of not playing with a full deck. :whistle:

[Easy Rider]

I DID notice last night, however, that the right side of the rear wheel was off by two notches compared to the left side. (Using the markings on the black bar) Could this have something to do with it?

Yes absolutely. Yet another reason that you should have a users manual (at least) before you go working on your bike. There is one available on here for download.

You failed to take those marks into consideration when you tightened things back up after the sprocket change. NOW you need to loosen the rear axle again and get those marks lined up......while paying attention to keeping the proper amount of slack in the chain.

AND THEN .......adjust the brake slack, pedal height and switch.

[Easy Rider]

I am sometimes accused of not playing with a full deck. :whistle:

Oh I think all the cards are there.......just that a couple of them are bent a bit !!! :shocked:

:crackup

[Water Warrior 2]

[quote="Water Warrior":1mx35kqc] I am sometimes accused of not playing with a full deck. :whistle:

Oh I think all the cards are there.......just that a couple of them are bent a bit !!! :shocked:

:crackup[/quote:1mx35kqc]
You may have something there. One for each ex-wife.

[mrlmd1]

Too much shuffling.

[aspirin]

With this fancy guide I'm gonna try this on my VL250 (which, if you didn't know, is practically the twin cylinder version of the GZ). Most of the parts are the same so hopefully it'll be as straight forward as it looks.

[blaine]

With this fancy guide I'm gonna try this on my VL250 (which, if you didn't know, is practically the twin cylinder version of the GZ). Most of the parts are the same so hopefully it'll be as straight forward as it looks.
It would be just as straight forward.Does the VL have the 15 tooth sprocket?
:) :??:

[Water Warrior 2]

You should be able to do the deed without any problems. The front sprocket can only be in one place and behind a guard the same as it's cousin. Might be a handy idea to wrap some velcro around the front brake lever to help secure the bike from rolling while you are wrenching.

[Slagugglan]

Just bought my sprocket off ebay :) came for 25€ total... Hope it's worth it!

[ucvro1]

My wife and I live down here in the Florida Keys, where the only road going anywhere is US1, 55mph 24/7, and not a hill for 500 miles. Sounds like this mod is exactly what we need to do so my wife can keep up with the traffic. She loves her GZ, so we will make it work! Great instructions, jonathan180i, you make it sound easy enough to do. As with all mods, I will update with results, as it seems some like the mod while others are unconvinced. We shall see...

[Slagugglan]

It worked... I yanked and pulled a bit to get the new sprocket on but I managed! Looks all fine! I will try it as soon as it stops raining!
Now to the next topic: chain slack! I am never confident with this, is there a precise way to tell how much slack is right?

Futhermore i have in my hand the 15t sprocket (it had just about 1000 km): is it normal that it shows more wear on the inside (the face facing the engine) than on the outside? It's just like the surface layer is worn off, but still? Is it normal? Any insights?

[ucvro1]

I posted that I am going to do this mod soon, and have all the tools and sprocket, but I can't find it shown here what torque (ft-lbs.) to tighten the sprocket nut to. I assume some enlightened being here on GZ250bike.com has that answer? Will you share it, or at least point out to me where I should have read it somewhere in this thread but was too lazy to see it?

Thanks!

O_o

[blaine]

I never torqued mine.I just tightened it good & tight and made sure that the washer was flattened against the nut.
:cool: :)

[cayuse]

65 ft-lbs, from page 3-7 in the manual.

[ucvro1]

Thank you cayuse....I haven't picked up a shop manual yet.

[jonathan180iq]

Gz250 Service Manual Download -
viewtopic.php?f=3&t=27 (http://gz250bike.com/forum/viewtopic.php?f=3&t=27)

[ucvro1]

I took a whole half on hour out of my very busy beer drinking schedule to do the sprocket swap today. It was a very easy job thanks to the fellow who did the "how to" at the beginning of this thread (jonathan180iq), and the only specialty tools were the big socket and a $19 torque bar, the old fashioned "how far will the needle go" kind.

Adjusted the chain slack (1/3") and took it for a ride down US1.

I like this mod! This is my wife's ride, her first bike, but I have put some miles on it just to get a feel for it. Now after the mod I can see and tell you that I think this is a good idea for anyone who plans to ride these bikes on anything other than short city jaunts. I can't say that there is any measurable difference, but the engine just seems to labour less, squeal less at 55MPH and higher. First gear is now more somewhat usable rather than simply a place keeper below the usable gears.

All in all, I suggest this mod for all on these bikes. I am impressed and wonder why Suzuki didn't put a 16t sprocket on these bikes to begin with.

Nothing was lost, but a more "civilized" ride was gained, for lack of a better term.

Thanks guys...

[Water Warrior 2]

1/3 inch chain slack from top to bottom movement ?? Sounds a little tight to me. You need more slack for the chain with the rear suspension compressing and reducing the slack. It is better to have a bit too much slack than not enough when you hit a dip or pothole in the road.

[ucvro1]

Thanks Water Warrior. The chain did loosen a bit after the ride as everything achieved a balance. I have a little over about half an inch of slack and I re-tightened everything up in the back so I think all is good now...

[ironhead1530]

This mod is awesome. Took me about an hour as a noob (including travel time to autozone for 30mm socket). The bike runs soooo goooood now. The bike seems to settle in nicely at 55-60 and first gear in useable now. Great writeup by Jonathan.

[alantf]

wonder why Suzuki didn't put a 16t sprocket on these bikes to begin with.



Because people like me live in the mountains :)

[Water Warrior 2]

Suzuki does a good job of gearing their bikes for the majority of riding conditions and expectations. OEM bikes right out of the crate with no mods whatsoever will do nicely for 90% of the riders out there.
Just for the experience I went up one tooth on the Vstrom front sprocket. That gearing made for a nice top gear RPM on the prairies at slightly above most speed limits. Back in the mountainous areas of home and all the curvy roads the stock gearing is the way to go.
Most bikes will feel better around town with a change to a larger sprocket up front but there is the out of town trade off that may not be of any real value and might actually make your ride more of a chore than a giggle.

[cibolorider]

My thanks go out to Johnathon180iq for the great post in the How To section concerning changing the sprocket on the GZ250 to a 16 tooth. I finished this mod today and I am very happy with the results. It makes my GZ run like I wanted it to. I got the same results Johnathon got and now I really feel like I'm riding a cruiser. Best $13 dollars I have spent on the bike. Thanks again Johnathon.

MOD EDIT - Post merged here.

[Skunkhome]

On chain slack , Since the rear sprockets are not necessarily concentric I would rotate the rear wheel while checking the chain slack and stop where it is tightest then adjust it at that point to have 3/8" ( book states 0.2-0.6" or 5-15mm) slack from top to bottom at the middle of the chain span. I would mark the rear sprocket with a dot of paint from a paint pen as a reference mark for future adjustments.

[bpdchief]

WOW what a bunch of replies.... I ordered the 16t sprocket Saturday evening - should have by Friday. Looking forward to giving it a run down these flat Florida Coast Highways

[Thumperville]

thanks to the OP for posting this handy info. i've put around 500 miles on my 2001 GZ250, all using the 15t sprocket. The motor has high revs going down the freeway, but rarely do i have problems maintaining 65mph, with the majority of the time i can get up to 70-75mph if needed to pass a car while driving on the freeway. The bike seems to do better than i expected reading others feedback about top end speed. the only problem i have with the bike are the high revs, it just sounds angry going down the freeway at 70mph.

if there were no 16t sprocket option i believe i would be happy with the 15t sprocket knowing its as good as it gets.

however, i've been reading thru the forums about 15t vs 16t sprockets, etc. i decided to order a 16t.

Today I swapped out my 15t sprocket for a 16t sprocket (after i built motorcycle stands that i also found how to make on this kick ass site) so after swapping the sprockets out, the first ride with the 16t sprocket i was pleasantly surprised. The bike seems to sound more at ease driving 1st thru 4th ; I only went on a 10 minute ride that by my choice had a 1/4 mile uphill section to test out the 5th gear. while driving uphill, i was only able to maintain around 50-55mph but i stayed in 5th gear.
towards the end of the 10 minute ride i was able to go 65mph but didnt seem to have enough umph to go any faster.

would mods to air intake / exhaust / carb be a step in the right direction if i want more top end speed?

for the time being, i am going to put some miles on the new sprocket.

[jonathan180iq]

Several people have suggested that some slight intake, exhaust and jetting tweaks have gotten them back over the hump with the 16T mod.

I was able to maintain my 80mph top speed even with the 16T with just a little tuning. By the time my ownership was over, the only mod I had done was a single lift of the needle jet. For me, 7/8 throttle was better than 100% full throttle. I probably should have just gone with a single size increase on the main jet, but whatever.

You can still get good speed out of the bike by using 4th gear to climb hills. I used to use 4th to get me into the 60 MPH range and then use 5th to finish it off. It may feel like the bike is really revving, but you're doing ok. I had a tach, and 65 mph in 4th is only a hair under 6500 rpm. It's not exactly pushing redline or anything. I wouldn't stay there all day long, mind you, as no vehicle needs to operate at 90% all the time. But it's fine for getting you over the hump.

[Skunkhome]

I think before I do anything with the gearing I would get a tach and FInd out just how many revs this bike is putting out at any given speed. Most of us are not used to listening to rpm's north of 4000 rpm. I have not seen a torque curve on the little engine but judging from the engine geometry (over square) I would bet that peak torque is somewhere above 5500 rpm and is made to scream. Anything else is just lugging the engine.

[cayuse]

Here's a posting I made over in the Gear Shifting thread:

I don't have a tach (yet) and I've never been sure of my rpm's so I thought I would exercise the noodle and came up with these charts.

There are some interesting figures here:
It confirms the tach results some are reporting in 5th gear: rpm's are ~10x mph
If you want to hear 8000rpm's go to 50mph in 3rd gear (!)
Seems to be OK, at least for short periods, to go 65mph in 4th (ie redline is just below 70mph)
Stepping up to 16-tooth gearing will bring you down below peak HP and torque at 70mph so don't expect to go faster with that mod.
I've always been impressed with the accel I get with this little motor when I let it wind out a little. Now, I've got some peace of mind that I'm not over-revving.

http://s2.postimage.org/L1Og9.jpg (http://postimage.org/image/2nhqri0ys/)

http://s4.postimage.org/HITiA.jpg (http://postimage.org/image/2grbzjrhg/)

[jonathan180iq]

I was just about to post that. :)

[Skunkhome]

Just as I suspected, you can see by that chart that you are way down in the torque curve when you are in 4th and 5th with a 16 tooth sprocket. Those people complaining that the 15 tooth is reving too high at 65 mph are actually at only a shade over 75% on RPM. At 65 mph it has not even reached peak torque in 5th gear.

[Thumperville]

i took my bike on a ride today that was 40 miles one way using the 16t sprocket. it was good and bad.

the first part of the ride i was driving directly into a stiff wall of wind and was only able to it up to around 55- 65mph at best... but could not maintain the 65mph speed limit in section of the road i was on. 4th gear would get me up to 60-65mph, but typically i was full throttle in 5th going 55-60mph.

i was feeling pretty bummed until the 40 mile drive back on the same road i was able to get it up to 75 mph with no problem, whenever i wanted it seemed. i even got up to 80mph in a few spots. engine felt pretty smooth and powerful with that tailwind lol!

now i just need to mount an airboat fan on a trailer that i pull behind the GZ250 and i'll be set.

[cayuse]

Thumperville, that's exactly what I experience in wind.

Like your avatar, BTW!!! :tongue:

[Water Warrior 2]

Riding into the wind is a real power sucker on smaller bikes. The GZ does have it's limitations but overall it is pretty hard to beat. In a perfect GZ world we would always be riding with the wind and slightly downhill. :lol: :lol: