Will they work?!

[jwatso89]

Hey guys, I've been perusing the site for a while and now that I finally have started my winter project of restoring a 1979 CB750K, I figured this would be the best place to ask questions about any problems I run into!

Diving right into things... the guy I bought the bike from included a set of the comstar rims with dual disks on the front and a single disk on the back, but the bike is currently only outfitted with a single caliper on the front. I was wondering if I would be able to use the front caliper on the back disk and use a set of calipers from a '82 cb750 for the dual front disks? Any advice is much appreciated!

[shinyribs]

As far as I know,none of the front and rear calipers interchange.The forks SHOULD have mounts for calipers on each leg,so putting the dual discs on your forks should be a easy swap.You will have to tee off for the 2nd brake line.There may be an issue on the speedometer drive.When i swapped from comstars to spokes I had to change to a different speedo drive.

[TOOLS1]

Welcome to the forum. Fitting the front caliper to the rear is feasible, but, you would need to fabricate a bracket. On the front; I do not think the K model has the caliper mount on the right leg. You will need to use a set of forks from  C model, or take off the disc on the right side, and run it as a single.
TOOLS

[cityslicker]

Mine is a K model and has the mounts on both sides.

[TOOLS1]

Isn't yours a SOHC? They did have mounts on both fork legs. However Honda changed the forks on the DOHC models.
TOOLS

[Ceruzziracing]

FWIW, on the 79 CB750F SS with Comstars, all calipers are the same. The rear uses same pads and rebuild part #'s as the fronts. Just swap the front end with a Supersport setup...

[sgtslag]

Tools is correct:  the '79 was single front disc, drum rear, by design.  The OEM forks will need to be changed out.  Best option is to swap out the fork legs, and borrow the rear assembly from a bike that had disc OEM rear setup.

Be careful of those Comstar rims:  I was told that some were made for tubeless tires, while others were made for tubes...  You don't want to find out the hard way.    Cheers!

[cityslicker]

Yea mine is single.

[jwatso89]

Thanks for all the advice guys, I've got a bead on a set of fork legs that should do the trick, as well as the swing arm from a super sport which will acomidate the rear caliper. As for the tube/tubeless comstars, the previous owner had new tires put on them and he rode it for a season so im willing to bet he got it right :)

[Ceruzziracing]

Where are you located? Just asking because I've just taken off the dual disc front end and replaced with GL1000 front end. Forks, triple trees, complete brakes, Comstars, etc...  I'm in North/Central Florida, would let them go for good price if you're interested.

[jwatso89]

I live up in southern ontario so i suspect it would cost a fortune to ship aha but thanks anyways man