ridejunky said:
It shouldn't be carboned up like that. Pull your head and make sure the arrow on the top of your piston is facing the front.
Please explain to us how putting the piston in backwards would cause a carbon build up on the intake side of the motor?
I'd guess also that it's some sort of paint coating.
All of the 2 strokes I have worked on, not very many, have had the openings in the rings toward the intake.
And from what I understand, if you have the piston in backwards, you'll more likely see a seizure as the result. Someone posted pics on here somewhere of a piston that had been put in backward, the rings were pulled out of the groove and the cylinder was trashed pretty bad.
It looks like there is some bubbling in that black coating, I'd hit it with a wire brush and see what the hell it is.