Thanks joe. The standard new piston was way too loose to use when compared to the original.
I had a close look and think about it and decided to re-use the piston as the marks were only light. The rings were also spot on with no wear. I did however install a new set of bearings.
After inspection of the original bearings I am confident they are the originals.
It's all back together however it's got good spark and nice clean carby so I'm confident it should be all good!
Thanks for the advice.
