Hi all, the 860 kit is staying, so I may as well sell the 650 pistons and barrels. They are the 1981 plated type (1983) with base O ring groove.
I believe the block is the same on R45s, also pushrods etc, but don't know about the head or whether the 650 parts can be simply fitted or if some machining or compression reducing base gaskets etc are required. From photos it looks like the edges of the 650 pistons might hit the wider gasket area of the 450 head. The 650 pistons do have a flat band at the edge and don't pop-up, but it's hard to tell. Of course it might simply result in 15:1 compression......
Since the head gaskets on all are the same apart from the 1000 and combined with my rough pic below, this seems to confirm the head will fit the barrel. But will the piston hit the head?
I'd like to know as someone is bound to ask now!