81 clark racing
02-16-2009, 03:19 PM
i just picked up a 05 400ex and when i start it up it sounds like a knocking noise coming from the motor. it sounds high in the motor. once warmed up it goes away and sounds good and u only hear it once in awhile. what do you guys think it could be? i no its not the valves i just adj them and rechecked them. i think it may be the cam decompressor or whatever? its 100% stock also. thanx 4 any help.....