Looking to get a little more punch out of the old 650 SN. If I find a 701 or 760, can I just plop it right in there? It already has the CDI from a 701 RN. Also, can I use the Coffman Sizzler from the 650 on the 701 or 760?
Basically yes. Your potential issues would be that the shape of the exhaust ports are a little bit different so your manifold might not work, there bolt pattern is there same but the port is a little different, it might be possible to match it up, not sure. 62t and 64x cylinders have 10mm exhaust studs but you can adapt them down with helicoils easily.
Other than that the only thing I can think of is the throttle cable might not be completely compatible.
How well it will all work with the pipe and ignition I don't know, but I think that's all as far as physical bolt-in compatibility.
Depends on the 701 also.. 61X/61X, 62T/61X or 62T/62T.
If you can find a 61X/61X it will be a super easy swap that will take a couple hours and really nothing to change or modify.
You probably could gasket match your 650 Coffmans exhaust manifold with a Dremel pretty easily.