KX250F cam chain skipped when lost coolant

Hi. While riding, a limb punctured left radiator and I lost a lot of coolant. I didnt notice it since the hole is small and probably was leaking slowly  and then the cam chain skipped , metal chain guide on the bottom is bent and valves touched the piston. Cam chain is new,its oem kawasaki. It doesnt seem to be stretched, it is shorter than chain i removed before.  What may be the cause of this happening? Thanks

Did either of your cams seize up due to heat? I have seen cam chains skip from a seized cam before.

Or a bad tensioner, worn crank gear, worn cam gears. The cam chain guides can also wear although I haven't personally seen it happen on these bikes.

Or the chain is worn "stretched" which can happen with age or if the tensioner is put back in without resetting. Did you reset that tensioner when you installed the new chain?

Edited by Dragon67

I took some pictures of cam and crankshaft gears. I think that at first cams seized due to heat, chain skipped over cams, then valves hit the piston and then chain skipped over crankshaft gears. 

P1240534.JPG

P1240536.JPG

P1240538.JPG

How doe the cam journals look? It will be obvious if a cam seized, as there would be score marks on the journals.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now