- Joined
- Sep 11, 2009
- Messages
- 228
I have had a number of 650 engines over the years and all have had "steps" machined into the face of the flywheel opposite the big ends (as per the picture). I've always assumed these steps were for piston clearance at BDC. I recently purchased another 650 engine in pieces and the crank (on the right in the picture) that it came with has a smooth faced flywheel, like an Atlas or Commando one. The whole section of the flywheel opposite the big ends has been machined down. My question is did the later 650s change the pattern of their flywheel machining to be the same as the 750?