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Tires and gearing?


lansingbird

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I figure 300 ft gearing on smaller motors to be at or slightly above peak hp rpm in 5th @ 80 mph at the end of the run; and tweak it from there; depending on rider weight and track conditions. You'll need the exact r/o of your tires, an estimated peak rpm and a gearing calculator. If you don't have a dyno sheet for the peak, you can put some low gearing on it so that it will be wound tight; then get the trap mph and figure what rpm it was. I'd use 72 mph - 75 mph for your motor. JMO.

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 Imo you need  different gearing , 14-41 is stock and pretty tall for 300 feet .    why would putting a longer swingarm  make it not  bog ?  its just gunna help keep the front end down once you do take off .    set  up to launch in second only ! if your starting in first you have already lost the race. your 8s will not be enough.  your swingarm will be fine ,  Key tip -  tires and gearing  are everything  even with a big motor, if your not set up right your not gunna win shit !  . I would start by going up at least to a 43 rear sprocket  , 

please do not listen to this guy....

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I know you think it's your gearing but to me it seems like its your motor , or maybe someyhing in the setup is wrong , sounds healthy and very good numbers but maybe could you tell us a litle bit more details on setup ? Lock up ? How much weight , how does it launch in 1 st gear ? Is there a flat spot on the power band ??? , I

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  • 3 weeks later...

Ok. Stock bore cheetah cub,18cc domes,vforce 3,shearer inframes, 35mm keihns, 21/11/8- 8 paddles 170lbs.

52 pilot 155 main and live in Kansas city ks.

I think I might be a little rich on the jetting will this cause bogging on second your lunches?

Cylinder compression is dead on 180 PSI

No air leaks at all!

No lockout just fast racing clutch and springs.

Do I need a lock out clutch with this setup?

 

Thanks guys lots of good info so far!

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I had a problem with my bike bogging on a 2nd gear launch. My motor is almost similler except domes, pipes, porting, jetting swinger length and paddles. I had the main jet and needdle tuned on a dyno and I fine tuned the pilot when I was over at the coast where I ride. I am at 152 main, 45 pilot and cel on the middle clip. I was at a 50 pilot when I was bogging trying to launch in second and I went down to a 48 and Now i am at a 45p. She launches good in second now with no bog. I have 13/44 and 22.11.8 10 paddles extremes. I think I can gain more if a mess with my lockout. Just trying to figure out what to use for weights. My 421 seemed to like leaner jetting with porting and different intakes. Maybe try dropping down in pilots?

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Sorry left a couple things out. 110 Vp and +4 timing. My thoughts exactly Badass banshee why is it bogging in second?? I think I'm rich on jetting. Just trying to play it safe and not lean it out to much. I am revving it plenty and dumping it. Going to waynoka in April and trying to get this resolved

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