i have a 00' 400ex and was wandering if a should get both front and back sprockets and whats size and if i should only get one which is better. i'm racing flatract and MX in the near future

 

Well, the countershaft is a lot cheaper than the rear one & does the same thing, up to a point. With the c/s cog you don't want to go smaller than 12 teeth due to the stress on the chain. but I would think that would be short enough gearing for hole shots, anyway. if you still needed more bottom end you could always go to a bigger rear sprocket. Behond that I can't give you any help as my thing is desert xc & I go the other direction on gearing.