i have a 400ex with a k&n power kit on it and i was wondering if there are stock mods to make the top end faster.thanx

 

Just take off your airbox lid, but be careful, dont go through sand or water or mud. You could also gear the machine "UP" By putting a 16 tooth front sprocket on it and any size smaller than a 38 (i believe thoze are the numbers) on the rear. That could add maybe 5-15 mph top end for about $75.00