CB650 vs SOHC CB750

Many questions:
What are the differences? I've read that the 650 is touted as having the performance of the 750 with the lightness of a 550. What about stock power rating? Top speeds? Real world performance? Tunability? Aftermarket part availability?

I originally was set on getting the SOHC CB750 but I found a super clean 1981 650 with a ton of cherry parts to go along with it and want to know how different the two bikes are. I plan to buy the bike, learn how to & ride it for a while then build it into a cafe racer. Thanks in advance for the input.

*Edit* Photos added

The best thing I've read about the 650 is that you can drop the motor into a 550 chassis with minimal fuss. Apparently the 650 chassis is a heavy turd.


that one is pretty tidy - I'd be tempted just to ride it and sell it on when you're done learning how to ride. There's always more beat up bikes out there to customize....

Poking round should tell you about comparative hp and speeds, but one thing to consider is the later CB650s (like yours) don't make the best platform because of the shape of the frame -- the dip for the seat and rise for the tank. Nothing you can't overcome -- others have -- but not the cleanest lines to start with.