John,
Great project thread. Wow, your bike is a unique and rare early model with very distinct and one-off characteristics, and found in beautiful Southern Ontario! What an amazing find.
I recently pulled the motor on my late model sandcast. It was leaking oil through the fins. I decided to bring the valve and cylinder head to Gord Bush Performance in Etobicoke Ontario. You may know him, he's a motor rebuild guy with a race history at Mosport. The cross-patch pattern was still visible and in good shape, so he cleaned them up with a light hone and I had valves done. I'm hoping to reassemble and have it back on the road this Spring. Its been one of the great thrills of my life having the chance to ride this thing around.
I have a gasket kit from Yamiya, but I wonder if you have ever used a supplier in Ontario for engine reassembly bits such as piston ring kit, etc. Cheers.