Thanks guys

I got it apart, the piston/ liner fit is very loose at the bottom end and the piston looks better
than the one in the photo but it has defintley been hot.
I run 22 % castor 5 % nitro fuel and run it as rich as I can on the ground so that it doesn,t
sag, go rich to much when the nose is held up.
I think I will invest in an inflight mixture control if I can fit it in somewhere.
I have got new piston/liner and bearings on the way.

Hawkflyer