My GZ250 gets funky in fifth...

[Cordell_Love]

So this is my first bike and I've been ridin for about two weeks. I love my lil GZ250 but I have a problem. The bike runs great except when I shift it into 5th, then bike lunges or lurches rhythmically every 5 to 10 seconds. You can hear the engine revving up before it lunges too. It only lunges in 5th and only if the throttle is open. Weird huh? Thanks to everybody for any and all advice on the problem.

[Sarris]

Try a new spark plug and clean or replace the air filter. If those are OK, try some carb cleaner in the gas tank. If your bike was purchased used, these items may need to be addressed.

Another thing to check is for a vacuum leak, possibly a disconnected or cracked hose. Specifically check the one connected from the carb to the back side of the fuel petcock. Hopefully one of these suggestions will fix your problem. Keep us posted.

:2tup:

[jonathan180iq]

Does this only happen under hard throttle?

If so, you may also want to check for a possible clutch adjustment.
Along those same lines, drain your oil and replace with motorcycle oil, just to be safe. Wierd things happen to some people when they use automotive oil with friction inhibitors.

Combine what Sarris mentioned with what I've said and you pretty much covers everything in the "simple-fix" category.

I'm gonna wager $3.57 that it's a disconnected vaccum hose somewhere. Of all the hoses that connect to the carb, only 2 of them are clamped on.

[Easy Rider]

I'm gonna wager $3.57 that it's a disconnected vaccum hose somewhere. Of all the hoses that connect to the carb, only 2 of them are clamped on.

I'll up the bid to $3.60! :)

Sounds to me like it is "lugging".

Cordell: At what speed do you usually shift into 5th gear? :??:
And how old is your bike......how many miles?

[Cordell_Love]

thanks for the help...i'll run down the simple fix list tomorrow. the bike's a 2007 and its got 8500 miles...lugging sounds like the right word for the experience...more throttle increase the luggin however the bike does it anytime i open it up in 5th...

[Easy Rider]

thanks for the help...i'll run down the simple fix list tomorrow. the bike's a 2007 and its got 8500 miles...lugging sounds like the right word for the experience...more throttle increase the luggin however the bike does it anytime i open it up in 5th...

OK, two things: A single piston bike is known as a "thumper" for a reason.....and that reason is most noticeable in high gear, under a load. It thumps.

So, if you shift into 5th at any speed below about 40 mph, it will sound a bit different. If you do it around 30 , it will FEEL different too. If you shift into 5th below 30, you are risking engine damage.

What you are hearing/feeling MIGHT be perfectly normal. At 8,500 you are probably due for some routine maintenance too. Check your manual.

[Cordell_Love]

hmmm, so that thumpin could be natural, weird, cuz it feels so jerky...I follow the shifting schedule found in the manual pretty closely, meaning I don't shift into 5th below 37 mph...i checked the air filter and hoses and didn't find anything, now i gotta figure out how to get those spark plugs out...

[music man]

Just in case you didn't know its only got one spark plug.

[5th_bike]

now i gotta figure out how to get those spark plugs out...
Take saddle off, get toolkit, get tank off, take left cap off cylinder, pop cap, use spark plug tool with something bar to unscrew spark plug.
To replace spark plug, carefully turn in with fingers, when stuck give it an extra 1/4 turn (not totally sure - look it up please) with the tool.

[Cordell_Love]

ummm, yeah, of course i know that it has only 1 spark plug...or not...thanks for the advice!

[Easy Rider]

hmmm, so that thumpin could be natural,

OK, here's where the disclaimer comes in:
The key words are "could be". It is impossible to know for sure without being there and I would HATE to cause you to ignore something that needs attention.
You need a second (experienced) opinion by someone onsite.

[Sarris]

You know, the more I think about your comments, maybe you're just up-shifting too soon. I normally won't even use 5th gear under 40 mph. With limited power on tap, you may just be lugging the motor, which can result in a "chugging" sensation. Why not have a pal or mechanic test ride it for you before you jump out your butt trying to fix something that may not need to be fixed?

Just a suggestion.

:)

[jonathan180iq]

...Or not shift into 5th until you are somewhere around 55mph and on relatively flat ground. Then let us know if it still happens.

If he is experiencing this in the higher speed range it certainly isn't normal.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~

You can hear the engine revving up before it lunges too.


Now that I just re-read this line, I think you need to change your oil. People who use some automotive oils get clutch slippage in the high gears. Has this happened ever since you bought the bike?

Easyrider, I see your $3.60 and raise you $0.40.

[Easy Rider]

...Easyrider, I see your $3.60 and raise you $0.40.

I call. :biggrin:

[Cordell_Love]

yeah the bike's been acting up in 5th since i bought it...ya know I've gotta leak where the exhaust meets the motor, waiting on some new exhaust gaskets as i write this, i wonder if that might be having an effect...

[Easy Rider]

i wonder if that might be having an effect...

Yes, might.

What other details have you left out of the story?? :roll:

[music man]

I have noticed that people do that on here quite a bit. My motorcycle runs funny when I am going 60, (18 posts and a lot of wasted answers later) oh by the way I have been pouring Aquafina bottled water in my oil and gas because my grandpa told me I could get better gas mileage that way. :bong: :crazy: :bang:


Later

[jonathan180iq]

yeah the bike's been acting up in 5th since i bought it...ya know I've gotta leak where the exhaust meets the motor, waiting on some new exhaust gaskets as i write this, i wonder if that might be having an effect...

Before I mentioned that you change your oil, I was going to suggest that, among other things, you do some general tighening of bolts between the carb and head and between the headers and head.

That's almost definately it.

These bikes are easy to knock out of proper jetting. An exhaust leak would make it not much fun at all.
There are no exhaust gaskets at the on the headers. The only gasket is on the muffler to header connection. Just grab 7 or 8mm ratchet and tighten up the bolts on the headers.

[Easy Rider]

waiting on some new exhaust gaskets as i write this, ...

There are no exhaust gaskets at the on the headers.

Mmmm....OK, so what part do you think he is waiting for ?? :??:

One needs to be very careful when turning header bolts.....in either direction. A broken one is NOT fun to fix. (Wonder how I know that?) :biggrin:

[5th_bike]

I'm gonna wager $3.57 that it's a disconnected vaccum hose somewhere.

You were right about the disconnected part, but I wonder if the exhaust pipe could be categorized as a "vaccum hose"... guess not.

Please donate my $3.57 to the forum. Thank you ! :rawk:

[Cordell_Love]

thats it...really...I added some seafoam to the gas today and that smoothed it out quite a bit. Gettin oil and sparkplug change tomorrow morning...so by headers am i to understand you mean the pipes that run from the engine to the muffler? Also, that there are no gaskets that fit between the headers and the motor?

[jonathan180iq]

Mmmm....OK, so what part do you think he is waiting for ?? :??:



I don't know what part he says he's waiting for. I've had the exhaust system off 3 times and have installed it 3 times and there are no gaskets between the engine and the headers.

...so by headers am i to understand you mean the pipes that run from the engine to the muffler? Also, that there are no gaskets that fit between the headers and the motor?

Yes. The pipes that come out of the engine and bend under the bike are called the "headers" or "head pipes". Once under the bike, they connect, via a thick metal spacer/gasket to the muffler, which is then bolted onto a spot on the swingarm.

When you look at the connection between the headers and the engine, you'll notice an oblong clamp on each pipe which is bolted to the engine. Those clamps are the only connection between the headers and the engine. If you follow this link, http://tinyurl.com/4w7djm, you will see that part #2 is called an exhaust pipe gasket. They come on with the exhaust system and I never could get them off. I'm fairly certain they are welded on there, but I'm not 100% sure. I do remember that they are metal and they wouldn't come off. What I'm saying is that they are part of the pipe. If a mechanic somewhere told you that you needed them and had to buy some, I would be wary. Like I've said, I'd had the pipes on and off about 3 times and at no point did I ever need to purchase a header gasket, since they are already on there.

[Easy Rider]

..... you will see that part #2 is called an exhaust pipe gasket. They come on with the exhaust system and I never could get them off. I'm fairly certain they are welded on there, but I'm not 100% sure.

First, are YOU the one who dropped a "wide" message in THIS thread ?? It only affects page 2 and this time,
it makes it look like I am the culprit (since the first post on page 2 is from ME).

Secondly, the exhaust gasket WAS a seperate part......the first time the pipes were put together. It is now "welded" on only
because of the dis-similar metals, a little moisture and HEAT.......LOTS of heat. :)

[jonathan180iq]

I guess I did wide post. I wonder why that happened...

Unless this guy's bike is different from all other GZs out there, I'd assume his gaskets are "welded" on as well.

Oh, and 5th-bike, I'm not paying up. The original story wasn't complete and, as such, admonishes me from any and all repsonsilbity to pay-up on any and all wagers due to section 42- article 13 of the Gz250bike.com membership guidelines.
Do a search, GEEZE! :)

[patrick_777]

I guess I did wide post. I wonder why that happened...

You should check out http://www.tinyurl.com

It will eliminate all of that, and there is also a Firefox plugin for it...maybe even an IE extension.

[jonathan180iq]

How do you turn a URL into a single word? I never did figure that one out.

[Magnar Infectus]

How do you turn a URL into a single word? I never did figure that one out.
Like this:
Word (http://www.gz250bike.com)

Word (http://www.gz250bike.com)

[5th_bike]

I'm not paying up. The original story wasn't complete and, as such, admonishes me from any and all repsonsilbity to pay-up on any and all wagers due to section 42- article 13 of the Gz250bike.com membership guidelines.
Do a search, GEEZE! :)

Aha, I smelled some male bovine manure upon entering the forum, and here it is!

"section 42 - article 13" yeah right - :tongue:

Considering the excruciating circumstances I will absolve you from your legal duty to pay up, rendering your indebtedness null and void - sorry dupo. And I apologize for not contributing anything remotely useful to this discussion. Back to business.

[Cordell_Love]

soooo my bike is different than all other gz250s out there cuz i gots no gaskets welded to my headers. i know this cuz i took'em off and looked...its just 2 smooth blued pipes, 2 clamps and 4 bolts. maybe the dominican dude who owned it previously took'em off and lost'em...my spanish sucked as bad as his english.

at this point i've changed the oil, oil filter, spark plug and put half a cup of seafoam in a full tank of gas...the engine runs smoother and a bit stronger, the lug still kicks in 5th but i've only gotten in up to 50...and the header connection farts a hell of a lot less for some reason...weird.

mahalo

[jonathan180iq]

Can you give me a photo? In the meantime, I'll look around and see if I have one for reference.

[Easy Rider]

maybe the dominican dude who owned it previously took'em off and lost'em...my spanish sucked as bad as his english.

put half a cup of seafoam in a full tank of gas...the engine runs smoother and a bit stronger,


I suspect the PO was screwing around with changing the pipes and lost them in the process.
I suggest you get some and put them on; this still may be part of your problem.

As for carb. cleaner, SeaFoam is not REALLY good carb. cleaner. It may be good "enough" in some circumstances but you should not get in the habit of counting on it.
Original Gumout Carb. cleaner (not mulit-functional stuff) or Berryman's B12 are much better.

[Cordell_Love]

alright i survived ike, got my power back after 17 days and got some answers...the gaskets were in there they were just so black that we thought they were just part of the exhaust valve. I chiseled them out and put the new ones in. now the bike farts when it warms up but after that everything's bueno. BUT it still lugs in 5th, at least at the speed i've got it up to which is 55 to 60...have fun with that!

[Easy Rider]

BUT it still lugs in 5th, at least at the speed i've got it up to which is 55 to 60...have fun with that!

When you consider that 5th gear really functions like an overdive and there is virtually no "pull" when your are in 5th, what you describe is probably normal. This is especially true if you have a 16T front sprocket.

There just ain't much left after 60 and having no windshield so that you have a 60 mph wind hitting you in the chest just makes matters worse.........isn't that right, Alan ?? :biggrin:

[alanmcorcoran]

My wife is attempting to return the non returnable windshield that arrived with the misdrilled strap, wrong mounting kit and missing parts. I have a 100 mile plus round trip to a wedding in Malibu next Sunday that I will be doing sans windshield. I think I'm starting to get used to it. Bear in mind, I wear the full face lid so it's mainly the drag on speed that's at issue.

I can easily go over 60 though. If I put my face down on the speedo, I can break 70. I don't have the 16T and I can get decent power out of fifth gear. My work commute doesn't offer much opportunity above 50 so I don't notice the wind or the speed issue much. It's the "pleasure" rides where I bump up against the limits.