YZ250 2004 2 stroke....weird tinny/clunking sound coming from engine??

[yammieman]

Hi there. Lately ive been noticing a weird kind of noise coming from my engine as im riding. Seems to be more so happening at high rev's/speed and happens intermittently. It kind of sounds like 2 big chunks of metal clunking together or like a piston or something is loose and hitting another piece of metal. The engine still runs, starts and has compression and I am still able to ride the bike but i just thought the sound it was making might be a sign it was on it's way out. I wouldn't of thought it would be a normal sound. Just wondering what it could be? Thank you in advance :)

 

[Ol'89r]

It kind of sounds like 2 big chunks of metal clunking together or like a piston or something is loose and hitting another piece of metal. the sound it was making might be a sign it was on it's way out.:)

Could be a worn piston causing piston slap or a worn rod bearing letting the piston hit the head or a detonation problem. Take it apart and inspect it.

 

[yammieman]

Could be a worn piston causing piston slap or a worn rod bearing letting the piston hit the head or a detonation problem. Take it apart and inspect it.

cheers for the reply mate :)
i didn't take it apart but i did use a compression tester and has full compression in it, so possibly not the engine/piston or rings.

 

[RM_guy]

A worn piston would not be caught with a compression test. You could have a ticking bomb and not know it until the piston fails. If it's a cast piston (all stock and OEM pistons are cast) it needs to be replaced after 40 hours or so. When was last time that was done?

 

[Ol'89r]

cheers for the reply mate :)
i didn't take it apart but i did use a compression tester and has full compression in it, so possibly not the engine/piston or rings.

No worries mate. It will take itself apart soon enough. :nod: :yikes:

 

[Rich Rohrich]

No worries mate. It will take itself apart soon enough. :nod: :yikes:

To quote Mike Perry from Kibblewhite:

"it suffered an energetic dis-assembly" :yikes:

 

[yammieman]

A worn piston would not be caught with a compression test. You could have a ticking bomb and not know it until the piston fails. If it's a cast piston (all stock and OEM pistons are cast) it needs to be replaced after 40 hours or so. When was last time that was done?

never had a rebuild done before. as soon as i changed the spark plug it was fine though. bike runs at full power and all....just makes a kinda tinny noise. i have a youtube video of it but can't link yaz cos the site won't let me post links