Yes it nipped up!
I.ve misled everyone though by describing a faulty front cylinder when it was infact the upper one. Everything else was explained correctly though.
Took your advice Andy and looking through the exhaust port and I see a piston with a bit missing from the edge of the crown, bugger.
When I got a Phutt type backfire I also saw a small puff of smoke from between the bottom of the barrel where it meets the crankcase as you would from a blown gasket.
In my ignorance is this likely to stop at a replacement piston and barrel or should I be looking further.
Advice , help , parts sourcing advice all welcome
Thanks, Mal.
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if it had a tail - it would wag