Topic: Swapping out swing arms from k4 to 78f cb750.

[la ca fe]

I have a cb75 k4 frame and have a "78 f swing arm with mag wheels.
I want to pair them up.
What is the best method of lining up the sprockets if the swing arms may be different?
Has anyone done this and made it work?

[Retro Rocket]

78 swingarm is wider on the left hand side so the frame top shock mount is further out to suit, 78 sprocket carrier is also 10 mm wider. The easiest route is to use the stock 74 swingarm and use the 78 wheels, use the K4 sprocket carrier and all you have to do then is work out how you are going to convert the rear to disc brake....

[Don R]

ah, the old F disc brake bugaboo.

[70CB750]

Yeah, I done it. Not exactly the same, since mine is K3 frame and 78 SS wheels

I have write up with pictures in my signature line - K3F.   You will have to modify your left top shock mount (as cut it out and weld new one in) due to wider swingarm and do something about the rear brake.

I used later Honda brake cylinder and alternated the K3 brake pedal to make it work. You dont want to use F3 brake cylinder, those are imposible to find and rebuilding kits do not exist.  Also the pedal will need different return spring.

Check out my build and ask me if you have any questions.