The piston is free and clear of any chips or dents. It just seems odd..the piston looked like it was rubbing on sandpaper.. im gunna say i didn't have a good feeling about this engine from day one. When I had to swap clutch housings on it I found alot shavings from machining on the outside of the seal but I brushed it off and ran it. So im going to say no more red arrow stuff
was just a thought thats all mate ,
now you've added the bit about the shavings on the seals, then that may point towards lack of care by whoever ported it,
if it was me i'd be curious and do a complete strip and flush everything out with brake clean on some paper towel just to see if theres any more metal/shavings in the bearings or anywhere else,
another thing is, are both the wrist pin clips fully home in there slots ?
possibly some damage from a loose or bent clip,