Gearing for XC Racing

[national425ex]

I race XC. My 400ex motor has the following mods; It was built by Tom Carlson of TC Racing. It has the 425 kit in it, A Wiseco Piston, TC National Cam, TC lightened crank, TC lightened rotor, and TC shorty Exhaust, along with a hinson clutch basket and hardened rockers. What gearing should I have? Thanks.

[national425ex]

bump...........Anyone?

[gcart2]

i know everone thinks hond is loco after their o8's but the stock gearing sounds bout right

[MO-EX-RIDER]

with that motor DO NOT put on a 14t, it will rev to quick and need to be shifted every 20 feet. maybe good on a super tight technical track but try stock and go from there.

[coryatver]

Stock! gearing lower is stupid it works like crap.

yeah on a 425 lower gearing would make you shift quick itwould be stupid

[upyours]

i ran a stock front sprocket and dropped 2 teeth off the rear(36t i think) first gear with a modded 400 ex is usless i was running a 426 motor i still have the quad but its racing carrer is over

[national425ex]

so stock gears is what, a 15 tooth? What about a 16tooth, Will that help with not having to shift as much in the woods?

[upyours]

i dont know off hand dude i think its 13 or 14 in the front go to world of powersports . com and check they have a oem parts look up i know that was the best working set up for me racing xc on that thing

[national425ex]

according to that website, the stock front gear is a 15 tooth. Which is what I have now. So your saying I should drop a couple on the rear sprocket. Or would adding a tooth on the front do the same thing.

[Pipeless416]

Originally posted by national425ex
according to that website, the stock front gear is a 15 tooth. Which is what I have now. So your saying I should drop a couple on the rear sprocket. Or would adding a tooth on the front do the same thing.

for some reason i thought that to go up to a 16 tooth you need a special case saver? also, a lot of people drop a tooth in the front.. however with that engine im sure torque is not scarce so stock may be the best way to go.

[fastredrider44]

On 1999-2004 I think, not sure about the year, the front stock sprocket is a 15. On the 2005- present, its a 14. 38 on the rear is stock for all years. I race XC and run a 14/38. I have a 426 kit and a stage 1 hotcam. Works fine for me. I ususally don't kick down into first gear much, but stay in third most of the time, rarely hit fifth, but I don't mind shifting between three gears.

[Ruby Soho]

i just put on a 14t front sprocket stock 38 in the back, wow. what a difference. muchhh more bottom end

[coryatver]

It feels like you have more bottom end but you don't. If you know how to use a clutch the stock gearing works the best then you don't kill your top end and make it slower then it already is

[fastredrider44]

I like the 14/38. It's factory gearing on many bikes, so I like it. I never top out anyway, so I didn't mind losing a few mph off the top. Makes my gear ratio a little closer, so its perfect for me. I've heard of people wanting 13 tooth and 40 tooth and stuff like that, but that's too much.

[04TRX400EX]

Originally posted by Pipeless416
for some reason i thought that to go up to a 16 tooth you need a special case saver? also, a lot of people drop a tooth in the front.. however with that engine im sure torque is not scarce so stock may be the best way to go.

This is correct. A 16 tooth front sprocket will not clear the stock case saver. If you want to gear higher, change the rear sprocket.

Ruby Soho -
You are right, a 14 tooth front gives you a lot more bottom end but for his motor mods, he doesn't need it. It will simply rev out too quickly with shorter gearing.