Topic: 72 CB750 owner interested in a Dual Disc setup needs help.

[CB750R]

Hello, I've been asked by another lister about using a set of 77 F2 dual disc front calipers, and the fork on the forks of the F2 to convert his front wheel to dual discs.  Can someone please tell us what may be involved in doing this? 

[kghost]

Check the FAQ.

Somebody asks this question about once a week.

[CB750R]

I didn't see anything on using a set of F2 forks, and Brakes on a stock 72 wheel. I'm just assuming, that this would be a fairly straight forward way to go, since this fork and brake combo was made dual, leaving only the wheel to convert.

[kghost]

The spacing for the wheel between the forks (and hence the triple trees) may be different.

I don't think you can use a regular wire wheel.

Since the caliper pistons are relativelt the same size and the K already has the bosses on the right fork why don't you do a dual disk on the forks you have?

[MRieck]

I have an F3 front end on my 75F- it is more involved than you would think. The rotors need to thinned to about 4.5mm and the OD needs to reduced. A spacer needs to be made for the right rotor. I Helicoiled the hub and countersunk the rotor bolt holes 42 degrees to use flat head metric allens so it wouldn't interfere with the speedo drive. The calipers needed to be shimmed slightly to to center the rotors. I made stainless lines which connect to a Nissin remote master cylinder. I guess my point is it is possible though it requires some work.

[CB750R]

Ok, so someones better off using thier own kit, and getting a second caliper/rotor/master cylinder, and doing it them selves then they are using any of the f2 parts to (the dual calipers, alone or with the forks) in making this happen?

[MRieck]

Pretty much.

[kghost]

Yup.

Directions in FAQ. 

[bryanj]

Early 750's need a mirror image caliper bracket that bolts to the leg. Yoshimura used to make thiese from magnesium, now i believe they are unobtainium!! Later forks you just bolt up another bracket. Both need a modified speedo drive that i have pictures of.

[CB750R]

Ok, Thanks guys, for clearing that up, sorta explains why I havent' sold em yet!!

[Geeto67]

you could use a 75-77 gold wing front end, bolts on triple tree to clamp and you get 38mm forks, aluminum rim and bigger brakes. As far as I know the cb750 wheel can be used but you still need the goldwing rotors to work with the GW calipers. IF you want a working speedo anyway, you are probably better off using a gw wheel. I am not 100 percent sure but I think you can use a gold wing front wheel with your cb750 forks but you will need custom spacers.

[Terry in Australia]

When I was restoring my F2 I had the wheel apart awaiting new bearings and I needed to move the bike, so I was surprised that a K2 front wheel was a perfect fit in the F2 forks, apart from the fact that the disc was too fat to mount the F2 caliper.

I reckon the Goldwing Wheel and speedo drive in the F2 forks, with an F2 axle, spacers etc would just about be perfect. The Goldwing discs are thin like the F2's, I'm (pretty) sure that the disc spacing is the same, and the F2 forks will slip straight into your mates '72 triples.

Only one way to find out! Cheers, Terry.

[kghost]

As far as I can tell the 78 Goldwing I have has the same rotors, calipers and wheels as my 77F.

But, that doesn't get you back to the spoked wheel.......

[Terry in Australia]

I had a 1975 Model "Lead Wing" and it had a spoked front wheel with a very nice 19 inch alloy rim. I often thought about trashing the rest of the bike and installing the front end on my K1, but I ended up selling it to a dealer who almost went mad trying to rectify all it's faults. I can't confirm that it was actually built on a Friday, but it sure acted like it! Cheers, Terry.