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-   -   Gears... 15/41 Stock v.s. 18/38 mod (http://www.gz250bike.com/forum/showthread.php?t=4676)

Jvacustoms 09-10-2011 12:23 AM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
currently when i ride to my moms house in the mountains it gets top speed of like 47 uphill and i feel like i am gonan get run over

JWR 09-10-2011 12:27 AM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Quote:

Originally Posted by Jvacustoms
I am looking for top end really not fuel economy or quickness just nice torqued up top end pull the hills and such with a greater speed.



Those two are on opposing ends.

Short answer...WRONG BIKE.

Water Warrior 2 09-10-2011 12:29 AM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Quote:

Originally Posted by Jvacustoms
currently when i ride to my moms house in the mountains it gets top speed of like 47 uphill and i feel like i am gonan get run over

Regearing for more speed won't help. You wind up dropping the RPM too much to develop any power.
As was said, the GZ is a GZ. It is what it is.

Jvacustoms 09-10-2011 12:32 AM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
and hp gains wont help the rpm issue ?

JWR 09-10-2011 12:34 AM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Quote:

Originally Posted by Jvacustoms
and hp gains wont help the rpm issue ?

If you improved the HP by 20%...

18+3.6= 21.6

My math is simple 2x0=0

It is a GZ.

5th_bike 09-10-2011 08:07 PM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Quote:

Originally Posted by Jvacustoms
currently when i ride to my moms house in the mountains it gets top speed of like 47 uphill and i feel like i am gonan get run over

Well you could switch down to 4th gear. At 65 mph in 4th gear the engine runs at 8,000 rpm which is not redline but the bike does not like to do such high rpms for a long time. At least in 4th gear you could easily go 50-55 and not blow up the engine.

PS WW - sorry but your 27% is kind of, um, off - you add where you should multiply. Look at my earlier post how to calculate the percent change in gearing, just multiply the two increases: (18/15) x (41/38) = 1.29... which is 29..% more. Moot though.

Jvacustoms 09-10-2011 08:13 PM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
So will a hp increase of 4hp suffice that kind of gear change ?

5th_bike 09-10-2011 08:19 PM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
The GZ is what it is. The design has been around for years and Suzuki is getting just about everything out of a 4-stroke 1-cylinder 249 cc that one can get out without over-stressing it. Also, if it were a piece of cake to add 4HP, everyone would do it. Please take it for what it is and if you don't like it, and 4th gear will not get you up the slope any faster, consider another bike rather than trying to get more out of the little GZ.

JWR 09-10-2011 09:12 PM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Just for fun...

http://www.gearingcommander.com/

15/41= 2.733
16/41= 2.565
18/38= 2.111

The GZ has a hard time pulling the 16 tooth sprocket.
But if it could pull the 18/38 it would run 115 mph.

music man 09-10-2011 09:20 PM

Re: Gears... 15/41 Stock v.s. 18/38 mod
 
Quote:

Originally Posted by Jvacustoms
So will a hp increase of 4hp suffice that kind of gear change ?



No because again we are talking about a GZ with 18hp stock, so you still only would have 22hp to work with.


If you add 4 horsepower, you MIGHT feel it a little when you are poppin around town, and you MIGHT go 78 top end instead of 74 (just an example). So you are gonna do all that work and spend all that money to get 4 horsepower (which you would have to prove to me that you squeezed out), to get very very little reward from. I would have a hard time believing that you could even squeeze 4 extra horses out of the GZ engine without cracking open the engine and doing some serious internal work, I mean that is over 20% horsepower gain!!!

And before you say yeah that is a 20% horsepower gain, so I should feel a real difference in power, again, we are talking about a bike that only has 18 horses to start with. I have a push lawnmower that has almost 7hp, Most riding lawnmowers have 20+hp engines on them, so you are not working with much on the GZ, Just ride it like it is, and enjoy it for what it is.


See your gear ratios are a good idea for more top end, if you are dealing with a bike with plenty of horsepower, and you also have to have plenty of torque to give up, but on the GZ you have neither to play with, so it is what it is.

Not to mention the fact that the GZ is so light that even at 60ish, it starts feeling very sketchy, so why anyone would want to go much faster than that on one is beyond me, I went 71 on mine one time just to see how far I could go, and it did not feel very stable at that speed, so I can't imagine pushing it much farther then that.

All these ideas you have would be awesome to do to a bike with a bucket load of power to play with already, but the GZ just aint got it to give.

So we are not knocking your ideas or your enthusiasm, just the fact that you want to try and do it to a GZ.


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