Topic: 1977 750 F to K frame swap

[Zax]

Hi,

 This is my first post (go easy on me). Search did not turn up anything even though I am sure this has probably been asked a few dozen times before. I am looking at buying a 77' 750 F but unfortunately it has never been registered in Canada. I have no interest in jumping through the hoops to get it federally and provincially inspected and cleared. I can get a K frame for next to nothing and the bike I am looking at is 100% torn down.

 My question is will the F swing arm mount into a K frame with no modifications to the frame or swing arm? I realize there will most likely be some work to be done in the rear brake department. Is there anything else I need to be aware of should I go ahead with swapping all parts from the F to a K frame?


Thanks,

Zach

[70CB750]

I am planning to fit 78F motor in K3 frame.  The swing arm should fit right in, but you will need to extend the left shock mount.

This is not first hand knowledge, but result of my research, btw:)

As far as the brake - my plan is to fix some kind of a bracket for it, but I am using CBR600 rear master cylinder.

[andrewk]

If the K frame you find is 77 or 78, everything should line up, and you'll be left only with figuring out how to mount a rear master cylinder.  The problem of the shock mount comes from the final drive being moved outboard 10mm in the last 2 years of production.  Late frame F to K (and vice versa) should be bolt on and go.

It's of questionable legality, but if it were me, I'd consider just swapping the vin plate over.  Much easier, IMO.

[Retro Rocket]

K frames up to K6 are shorter by about 2 inches in the rear, that will make it hard to mate up the F model rear section and the seat...

[seanbarney41]

It's of questionable legality, but if it were me, I'd consider just swapping the vin plate over.  Much easier, IMO.

What about the vin stamped into the head tube on the other side?

[Tugboat]

^What they said.. the reason the F2/F3 & K7/K8 bikes have the extended "shoulder" on the upper rear LH shock mount is that, in 1977, Honda switched to the wider 630 chains, and had to move the front sprocket out 10mm so the 630 chain wouldn't rub on the cases. 10mm offset in the front required 10mm offset in the back to keep the chain straight. This meant that the swing arm had to be wider, and thus the 10mm offset at the top so the LH rear shock is straight.

Good luck!