scrap that video, I've since had to rebuild the engine because I hadn't locite'd the screws in the cooling head. When I took the screws out loads of dirt fell in the engine so I had to strip it down before I ran it again. Whilst I did that I looked at the piston and sleeve, the sleeve had a mirror finish at the top end, and the piston had some slight wear at the upper edge too, was quite interesting to see them after they had bedded in together.

Anyway, I'm going to have to re tune it all now because I had added the two shims between the cooling head and the engine when there was already a pair there! I only noticed just now, so I have broken in my engine in with slightly lower compression I guess! I am assuming the engine will have a bit more power now I have the correct number of shims. Am I right?