gearing for yamaha shifter

80Jr and Sr, 125 Senior, Stock and Masters

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Shawn Hendrickson
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Joined:Wed May 28, 2008 4:57 am
gearing for yamaha shifter

Post by Shawn Hendrickson » Wed Jun 11, 2008 4:47 am

I am all new to this and want to get right or close the first try. I just built a shifter kart with a yz 125. I need a rear sprocket to get it going. Katy is the only track I will go to just for fun, not to race. What gearing do i need? I talked to a couple of Honda guys, is the yamaha pretty close? Please help I am ordering a chain and sprocket today. I want it to haul. I have a 14 15 16 18 and 19 for the motor, just need to know what rear sprocket.

Ray Aguirre
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Post by Ray Aguirre » Wed Jun 11, 2008 8:29 am

Shawn,

Brad had this comment:
I tried to race at the first race but had a broken reed so the motor wasn't running right. I had a 15/28 but probably needed a change maybe to 15/27. I run a stock Honda but I'm a heavier guy, crossing the scales at about 420, if you're close to 385 it might be different.
He was suggesting a 1.8 ratio.

Shawn Hendrickson
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Joined:Wed May 28, 2008 4:57 am

thanks

Post by Shawn Hendrickson » Wed Jun 11, 2008 8:42 am

I will try a 15 27, hope it works.
Shawn

blucido
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stock 125 gearing

Post by blucido » Thu Jun 12, 2008 8:48 pm

Shawn, when we came down to your track for the SWRC race and ran the track clockwise all of us in the stock 125 class were geared at a 15/24,and turned times in the high 39's on Sat. Sun was hotter and a flat 40 was our best.This was on Brigestone "C"s for the event,if you run MG yellows it could shave off a 1/2 second or more we find.

hickmankrt04
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Post by hickmankrt04 » Sun Jun 22, 2008 11:00 pm

Shawn,
have a 94 yz125 , gearing we run at katy is 1.50 . gives you just enough over rev down the straight. Is your yz stock or mod ?

Shawn Hendrickson
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Joined:Wed May 28, 2008 4:57 am

motor

Post by Shawn Hendrickson » Mon Jun 23, 2008 12:33 am

Mine is a mod. It has some port and cylinder work done.
Shawn

Shawn Hendrickson
Posts:11
Joined:Wed May 28, 2008 4:57 am

gear

Post by Shawn Hendrickson » Mon Jun 23, 2008 4:24 am

Actually now I have a 15-26 gear and it feels short. I want it to haul top speed. I am going to put a 16 or 17 on the motor. I will go to Katy next week for the first time, I just got it running and tried it out at the airport this weekend. I did notice the shifters are strung out about halfway down the straight. Why are they not geared different? I went to the race and watched Sunday for the first time. Those shifters haul but they could get another 20mph on the straight geared different. Does that just make them weak out of corners? I might put a CR 500 on mine soon. I am not racing, just playing. I want mine to go 200. LOL!!!

hickmankrt04
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Post by hickmankrt04 » Wed Jun 25, 2008 7:05 pm

just got back from running my crg with a cr125 modified.
put a 17-24 on for gearing need to add gear going to 17-25=1.47
top speed was 81-82 mph at the end of the straight.my speed will go down but lap times will be better. I practice on mondays , because it my day off.

Shawn Hendrickson
Posts:11
Joined:Wed May 28, 2008 4:57 am

gearing

Post by Shawn Hendrickson » Wed Jun 25, 2008 7:18 pm

Thank you!

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