Posted this in Kawasaki forum, but thought this forum might provide a larger knowledge base..

Over the last couple of rides the motor on my KFX400 has developed a very loud knocking sound from the right side of engine.
Thought it might be the valves at first because it wasn't too loud, but I checked em and they are within spec.
Listened close to motor and the sound seems to be coming from lower down behind the oil filter I think. Have not checked the cam chain tensioner yet.
Any other thoughts besides taking it in to the stealer?

 

Anyone?

 

Any info please?

 

On sleds anyways that usually means a crank or crank bearing. Not good, hopefully thats not the case for you.

 

check to see if ur head bolts are not stripped out. on my old EX it would make a really loud pinging and i tapped out the head bolts and replaced them and it went away.

 

ouch -- rod bearing?

 

crank, valve, or rod?? Thats my suggestions..?

 

if its an 03 it may be the cam chain guide is worn where the tensioner makes contact or the chain is stretched. a few 03's had some trouble with this