Thank you so much, now i know it can be done reasonably easy
But first I want the original engine to run so I can get it registered and plates on, and then I can start the rebuilding with the Runner engine.
I have now opened the original Fly engine, and I can see that J.costa vario and Malossi 3111393 cylinder kit have been fitted.
But now I know what has gone wrong, the flywheel fan has lost a screw which has shattered the flywheel fan completely, and it has been running for some time so the engine has become VERY hot, and it has then caused one slide rail for the cam chain to melt , and one valve seat has come loose so that it sat skewed between valve and cylinder head, and the valve has become slightly skewed.
The camshaft and rocker arm has also become a bit worn, and should probably also be replaced.
Incredibly, the cylinder appears to be in really good condition, I would have thought it would have heat damage
the valve seat I think I can push in again as it does not seem to have been damaged, but I will probably have to order the following.
Valve
Camshaft
Rocker arm
Cylinder gasket kit
Flywheel fan
It will probably be easier to find a used cylinder head
I forgot to take pictures before I parted it all, but here are a few after