Head Gasket,Cracked head or hole in piston

Carl
Had a reply from Bob confirming my thoughts.
these being Detonation weakened the pistons and the hydrodraulic issue was trigger to failure.

Glad to sort this out and thanks to all replys and especially Carl for his referral.

I have two weeks to our major Nostaglia meet so need to get on my bike to get it back together.

Cheers

Benton