i have a 400ex and it is piped, jetted, and K&N air filterd with the air box lid off, and i was wondering if i would lose alot of turque if i changed the sprocket to a 36 back?
and what size front sprocket would i have to get so i wouldn't have to modify the chain any, mabye a 16 tooth front and 36 tooth back, and with this combo would i still have plenty of turque with the mods listed above???

thanks

 

You should be OK with the 36. With the stock engine you will not be able to pull top end with the 16T. Try the 36 if you don't like it go back to the 38 in the rear. when you get some engine work done try the 16T in the front. The rule of thumb is that one tooth in the front is about 3 maybe 4 in the rear.