Better, but with the same old same old.

I've fired it up again and its still not performing correctly. Its better, but not right. I fear the crank shaft is suffering again. I'm going to look at the cylinder heads next and perhaps make two new inlet valves and seats. I'm thinking it was a mistake to make the inlet valves so big, so I'm going to reduce their size. Too much mixture is getting into the combustion chamber and ignition is taking place far too advanced of TDC. Its OK lower down the rev range, but when the throttle is opened it tends to labour and get extremely hot.

Back together again.

It's good to see it all in one piece. Assembly is by no means straight forward, and takes a considerable amount of care and patience. One of the trickiest parts is fitting the gudgeon pins. There is a PTFE pad on each end of the pins and you have to be careful not to push the first pad out of the other side of the piston. This is especially tricky when fitting the second pad as there isn't much space for them to fit between the ends of the pin and the cylinder bore.

Reassembled and...

...rarein' to go!

Another issue is the valve timing. The gears are cross helical and you have to "aim" the camshaft as you fit it because the working position is a few degrees away from where you first insert it due to the helix in the gears. I think I've got it right, but only testing will tell. I may have to advance or retard it a notch.