Top end noise. What is it??

[bk250]

I have a 99 yz250 that I picked up last year. I have noticed a sort of tapping sound that seems to be coming from the top end. It is clearly loud enough to hear but not so loud that it makes you think it is about to do any damage.

Any ideas on what this noise could be from? I am about to do some work on the top end and carb so any recommendations on what to look for when I am in there would be appreciated.

Thanks!!!

 

[rigi144]

is it a sort of metallic tapping noise, like every time it turns over, it makes a metal-against-metal click? if so, then i have the same thing on my xr200 and i too cannot figure it out.

 

[83XR500R]

Could be piston skirt slap...from a worn or improperly sized piston. Doubt it's the wrist pin...but it could be...you usually end up with bad vibtations though. RIGI144 CHECK YOUR VALVE CLEARANCES ASAP!!!

 

[rigi144]

why, what will happen if i dont, and how long will it take for it to happen?

 

[bk250]

It doesn't have a distinctive metallic sound to the tapping, but then again there really aren't that many options for it to be other than metal, are there? ;)

 

[83XR500R]

RIGI don't really worry about what will happen...lot's of things can happen...your bike will last almost forever if you stay on top of maintenance. As far as how long?....just get a shop manual and fix it...it's child's play on those bikes. You're basically asking "How long can I ride it like this without fixing it before I have to dump $$$ into it?". Not trying to be a wise ass or anything...just honest.

 

[rigi144]

are you absolutely positive that its the valve clearances from what i described? and how do i fix it cuz the maual doesnt tell me how to fix anything, just how to take it apart, inspect, and assemble.

 

[rigi144]

never mind, found it.