With enough patience it isn't all that hard to find bits, I have spent numerous hours digging through bits at the local bike wreckers, the front calipers off of a cx500 fit but they look different to the origionals IMO they look bette, the rotor for the alternator out of a cb900 fits, the reg/rec out of a cb750 fits but you do need to change a plug, a lot of the bits out of the cb550 fit because the 650 was built on the same tooling as the 550, this is my experience with these old girls, but I cannot enphasise enough that having a good relationship with the local wrecker is the most important part of doing up these old bikes, Ross at Tiaro Motorcycle Wreckers has been a godsend to me.