I just bought a 01 400ex about a month ago. It has an fmf pipe,a rev limiter,k&n air filter and 14 tooth front sproket. my problem is that it wont out run my brother in laws bone stock 99. It seems to me that i should be able to pull him through the gears and give up some on the top. just wondering if anyone had a suggestion or two?

 

is it jetted propperly?that could be your problem,is 14t geared up or down on the 400?and welcome to the forums.

 

15 tooth is stock on the 400EX. You may try a stock 15 or even a 16. Depends on the riding you do. I run a 16 on my 440 and it still has plenty of bottom end. Remember one tooth in the front is equal to about three in the back. And just in case you didn't know the small in the front the faster you will use up your gears opposite in the back.

The rev limiter shouldn't do much for you as the 400 doesn't make much power over the stock rev limiter...check your jetting...you could be rich...also greatly consider rider ability. Switch quads with your brother in-law and see what happens.

 

Thanks for the help and the welcome.I ruled out rider ability as we did switch under lots of conditions,sand dunes,dirt road ect. Where could i get some info on where i should be on jetting? Also why put a rev limiter on if it doesnt help much and should i consider going to a stock limiter?

 

you need to check and or do a few thing.

1. what is it jetted at?? keihin jets or dynojets??
2. adjust your throttle cable so you only have 1/8 to 1/4 inch slack in the lever. if you have more than that, the carb isnt opening up all the way.
3. put a 15 tooth sprocket back on the front.

 

The front sprocket is too small. The gears are winding out too fast. WHat size are your rear tires? It you go up to a 16 tooth front sprocket you will be sure to beat him

 

try using the stock 15 tooth befor u get a 16