engine help!!!!!!!!!!!!

[ohbaby]

i have a 250x with a knocking noise form the top end. what could this be? i can ride it but am afraid of blowing it up. any sugjestions?

:macho

[mojoe2878]

it could be lots of things. worn wrist pin, worn rod bearing, mis adjusted valves, piston slap, worn timing chain, etc., etc.
you need to take the topend apart and check it all out to find the problem.

[ohbaby]

how can u tell if the timing chain is worn?

[mojoe2878]

pull the valve cover off and see if it has excessive slack or play in it up and down and check the links where they connect to each other for wear.
if its the chain it will be more of a loud ticking, not a heavy knock.

[Glamis400ex]

There is a given spec for chains and it's all related to slack. I believe they measure it from pin to pin. Look in your manual and it probably lists the maximun legnth between two pins.

Glamis

[ohbaby]

thanx