I have a 100% stock 400ex and i would like to put a set of fast sprockets on it. Could you please tell me what the stock tooth numbers of the 400ex sprockets are and could you please tell me the best combination of front and rear tooth sprocket to make it as fast as possible....well so it doesnt hurt it. Thanks Jerry

 

The stock gearing is 15/38 and all I would do is go up a tooth up front or else you won't accelerete at all.

 

id go up one on the front youll will be surprised by how much faster it is

 

Alright. Thanks everybody.