no nothing like that, it looked alot like a splatter effect.

it looked like rust particles on the top of the piston but it wasn't rust. it's hard to explain, and i cleaned most of it of, but it seems like an oil that burnt on the top of the piston, or some sort of gluey substance. it is still on the inside of the outlet of the exhaust port on the walls.

it is a medium brown colour so it isn't burnt on, and seems to have dried on at a low temp.

i've never seen it before. i'm putting it down to oil residue left during the construction that might have been in the bearings possibly. i'll see if i can get a pic of the remaining bits of the "stains"