Topic: CB750 vs. CB550 Frame

[BrosefStalin]

Hi All,

Internet and forum search yielded no results. I am looking for the dimension differences on the early 70's CB750 and 550 frames.

Not looking to do a motor swap, I'm just looking at sizing. It appears that frame hoops are made for both models in the same size, leading me to believe that they are extremely similar from the tank back.

Any input here?

Thanks.

[calj737]

Seat rails are very similar dimensions, as are the swing arm widths (not lengths). I would suspect the K models of each would be pretty same (purely for an aftermarket hoop).

[BomberMann650]

I'm not certain dimension is as relevant as design in this instance.
750 frames have more in common with a moto-guzzi than it's little 550 brother.

[Scott S]

 I once bought a 550 engine from a guy and he threw in an untitled CB750 frame. He claimed he used the 750 frame with the 550 engine for racing. Don't know how true that is or how the engine would mount. I kept the 550 engine and carbs and gave away the frame.