Hi,I have an 06 trx250ex with the sport clutch and shaft drive. It started making a noise yesterday and I have no idea what it could be. It sounds like a whine and increases as you give it gas. I can also hear a lite rattle. The noise is there from idle through all gears. There is no power loss and it shifts smooth. It does not smoke... any ideas where i should look? sounds like its comin from the top end somewhere,is there no cam chain tensioner? thank you!

 

I've been thinkin,could it be the one way starter clutch or needle bearing going bad?

 

I have an audio clip if somebody thinks they can help...

 

Did you ever gigure out what was causing the noise? I have one and its making a similar noise, sounds like gear whine.