whats stockgearing om 400ex?

[660r2a400ex]

what is the stock gearing on the 400ex? i ride mostly wide open on farms and private roads , miles and miles of wide open areas, my buddys kfx/Z 400 is stock and so am i and he tends to pull me slowly, figure i would put some top end sprockets on my bike and trick him one day! also will a degree key from sparks help a little? can some buddy help me with the stock front and rear gearing and what gears do you think would help me gain around 5-10 mph?

[Silverfox@C&DRacing]

stock gearing is 15/38, I run a 16/37 gear combo seems to work good. I know others run different gearing and will give you some suggestions ;)

[turnandburn]

look on sidewinders sight they have a gear ratio chart. The lower the ratio the more your top speed will be but you might sacrafice some low end. Maybe check to see if you are getting a true full throttle opening could adjust the cable.

[660r2a400ex]

i am pretty sure my throttle is opening all the way, i think the kfx is just faster then me by a hare and when u have 3 miles of staright away it really shows i am use to my old raptors topend and miss it a little, so i am going to go with sprockets, not to worried about low end, with the 16 front sprocket, will i have to take my billet case saver off, i dont want to mess with that, does the 16 fit up there easily?

[turnandburn]

probably just have to shave it down some. should fit fine

[cals400ex]

yes, you may have to shave it down some. however, don't expect to gain 5mph with a sprocket. it will probally not make that much difference up top on a stock bike.

[660r2a400ex]

y not i am going to put a sparks key in it to help it get through the gears and rev out quicker, do u think a rev box would be a better mod for top end?

[Greg Z]

no rev box.... dont do it the EX stops making power at 8000 RPM