My YZ250 is making a very loud knocking noise about where the little spinny deal shoots the coolant around. im pretty sure thats where the noise is comin from. but i have no idea what the noise is. and it keeps on over heating, so i dont know. if anyone has the slightest idea, or clue, let me in on some info, thanks





-aaron

 

If I understand you then I'd say that you are talking about the water pump impeller. If it's making noise and overheating then, now I've never taken one apart but it sounds like the impellar has come apart. Theres not much to the cooling system so pull off the cover plate and look at it.

 

A lot of yamahas (including the banshee) use a plastic water pump impeller that can melt or break. You could also have a bearing going out. The gear that turns the impeller is plastic so it could be stripped. You will have to take the clutch cover off to remove the impeller, but there should be a cover on the outside.

 

alright, i took it apart, and it seems the impellar is fine, and it doesnt have anything to do with the damn coolant system. i belive it has something to do with the power-valve. it still keeps making the noise, so i guess i will take it apart soon.

 

Ok you got me then, my last dirt bike was a 78 yz400, I haven't needed to do anything on my 2000 yet.