Hi guys,
My KLX250 has devolped a really strange noise. It's like whirring or ratchet type noise, definitely not timing chain etc. I have found that the crankshaft moves inside the bearing sometimes (bearing remains still) and I know that can't be right. Also, the crankshaft shows signs that it has been hot but maybe that's from the manufacturing process? I've marked the bearing and crankshaft so it's visible to see what I mean. I'm thinking the bearing has seized momentarily and the shaft has spun inside the bearing before 'freeing' off again but now the bearing is damaged. The oil has never been low and I change the oil every 3000km. Anyone experienced something like this?
Colin

 

Insteresting stuff. The only whirring I've had was on my R6 and the stator wasn't tightened properly/fully onto the cover.

 

I'm pretty sure the discoloring is from induction hardening on the cam chain sprocket.
If the bearing was also discolored, then I would be worried. Yours appear to be fine.