I acquired the 2nd engine for the TT500 a while ago and the engine was rebuilt by Roger over 12 months . It’s then sat on the bench in my garage since June last year, waiting for an opportunity to get it into the bike.
The original bike had run well on the points ignition, but the spare engine’s ignition was rotten with plenty of water ingress. I’d bitten the bullet and ordered a Power Dynamo ignition unit having had some good results with a previous unit ordered for the Husqvarna Sportsman a couple of years ago. .
The new engine is also a 1T1 but has a Wiseco 4mm oversize piston, to take it to 540cc. The cams is original (something like a White Brothers cam would be nice) and the crank and conrod were good so have not been replaced, for now.
The oil feed pipes to the head has been replaced with the upgraded Kedo item , which seems like a very good idea and a weak part of the original design.
The decompressor worked initially, but after the initial start, you have ease the piston over TDC before giving the bike a good wollop on the kickstart. The compression has been increased from 9:1 to 11:1. The engine sounds good and runs sweetly, and picks up nicely. Full testing needed on the track but all seems good.
For a final flourish the front mudguard was changed as the later 1979 item was a bit big and flapped around a lot when the going was muddy.