Piston is black

[JSY0829]

I recently purchased a used Losi Muggy and after taking the head off the mill...the piston is black on the top. Great pinch and it runs great. Also holds a nice temp. Is there anyway to get rid of the "black" on the piston top?

I did a search for black piston...little confused. Would it be ok to take fine grit sandpaper(2000 grit) and oil and sand it off real lightly? Someone mentioned using a dremel tool. Any thoughts?

 

[MotoGod]

You could remove it if you really wanted to, but it won't do any harm. Sounds like just carbon build up. If you do decide to remove it with sandpaper BE CAREFUL ;-)

 

[JSY0829]

You could remove it if you really wanted to, but it won't do any harm. Sounds like just carbon build up. If you do decide to remove it with sandpaper BE CAREFUL ;-)

Yeah, it runs great. No issues what so ever with the mill. Just bugs me that it's black on the top of the piston. Am I right...it's caused from running too rich?

 

[MotoGod]

Typically yes. If it's running great....I wouldn't muck with it ;-)

 

[revo_rob_1984]

I agree with moto, if it ain't broke, don't fix it

 

[olds97_lss]

Just typical build up. Usually you can get some of it off by using a paper towel with alcohol on it. I wouldn't sand or dremel it. That will cause there to be microscopic grooves in the top of the piston which could cause cracks when it's running.

 

[Lessen]

I completely agree with olds. Do not sand the piston. DO try to clean it with alcohol though. The only reason I would do that is because the color of the piston can be used as a guide as to how the engine has been running. The piston really should never get that dark if it's tuned properly. It'll have a dark area generally offset in the direction of the exhaust port but it shouldn't be black all over.