80 CBX dual piston caliper upgrade

[Samelak]

Using the 80 rotors, what donor bikes are used for the dual calipers (front & back)?

[steve murdoch icoa #5322]

Lee, i used '81/'82 CB900F.

[NobleHops]

Hopefully Dave or Mike will chime in here but there's a little more to it. The swept area is different. This got clarified in some thread when I was asking about it, I ended up with 900f rotors and calipers and brackets in the front, and 900F caliper plus prolink rotor in the rear. Not saying it won't work.

Lemme go hunt this up...

N.

[daves79x]

Best bet is as Nils said - complete 900F set-up up front, which is different from any CBX parts. Rear can be complete 900F stuff also, but Pro-Link CBX will work there as well (as well as a few others, but those listed are most commonly found).

You will also need new brake lines front and rear. Not an overall big job once correct parts are found, but you do need ALL the correct parts.

Dave

[NobleHops]

OK, this is where we explored the issue on my bike Lee:

viewtopic.php?f=102&t=6650&start=15

N.

[EMS]

In order to make the term "swept area" a little more easier to understand:

The early (79/80) CBX brake caliper single piston has a larger diameter than the later model CBX or CB900F dual pistons do. As a result, the brake pads for the single piston caliper are wider than those for the dual piston calipers. That fact also reflects in the brake rotor. The contact area on the rotor for 79/80 brakes are wider than on the rotors for later bikes or F bikes. You could use later dual piston calipers on early rotors,but the narrow brake pads would swipe a narrower area on the rotors. It just would not look right after a while, because part of the intended contact area on the rotor would not be touched by the brake pads and would most likely corrode.

[Samelak]

Time to revive this thread... I thought I would get some more life out of my stock brakes, but after rebuilding my front left caliper a second time, it's seeping again. So I am going to look on ebay for some cb900f calipers with mounts. I already have a set of rotors from cb1100f gold boomerangs. If this sounds like the right combination, let me know. Just to be sure, will 1982 cb900f caliper mounts bolt right to my 80 CBX?

[daves79x]

Rotors from gold wheel will bolt on OK. '81-'82 900F parts work and bolt right on. Also '82 750F, a couple of Nighthawks and maybe the CX series that had twin piston calipers. Many others of the era had the anti-dive on one fork and the mounts won't work from those. 900F most commonly found.

Dave

[Samelak]

Do I need a different master cylinder or will the stock CBX suffice?

[EMS]

Your stock mc is fine.

[Samelak]

How about the rear brake? I have the rotor from a cb1100f. What do I need in addition to install a dual piston caliper?

[Samelak]

Anyone with experience with converting to a dual piston back brake?

[daves79x]

If you mean that you have a Canadian 1100F rear rotor, then a rear caliper and hanger from a Pro-Link, 900F or similar will work fine. You'll also need all-new brake lines front and rear. Fittings at the calipers have to be angled. Get a rear line for the Pro-Link and lower 2 front lines for the Pro-Link. Spiegler custom makes anything you want.

Dave

[Syscrush]

FWIW, my '79 is set up with gold boomies (presumably Canadian) sporting CBX rotors and CB1100F dual-piston calipers. The rear retains the CBX rotor and single-piston caliper on the CB1100F wheel.

[mrfallover]

Can someone post a picture of their conversion? That would be helpful.
Thanks.