Twin Piston Calipers on a '78 GL

[tomk1960]

A good friend of mine who was a Honda dealer in TX for many years has been watching my progress with my 78 GL. Today he asked me why I was sticking with the stock single piston calipers. He suggested bolting on some dual piston calipers like the ones used on many of the early-to-mid 80's Hondas. I didn't think it was possible, since bolt patterns, geometries, etc. may vary. I wasn't sure that there was a caliper hanger that could bolt right on. Well I'm really happy that I listened to him. When I got home, I grabbed a spare right caliper and hanger from my stock of "F" parts. Guess what - it bolts right on and everything appears to line up perfectly!



Someone here must have done this before - maybe many of our members have? How did I not know this until now? It even looks like the brake lines will be the correct length. Instant brake improvement!

[Oldewing]

WOW,

How did we miss this all the time...

[Whiskerfish]

yea really!!! awesome bolt on upgrade!

[Sugs]

What bike are those twin calipers from? Not sure what you mean by "F".

[hatchward]

Hey guys “Old Fogey” did this years ago.

[Oldboy]

So did I.....

[tomk1960]

Hey guys “Old Fogey” did this years ago.

This is why I asked if I someone else has already done this. I figured someone must have and I just missed the post. If this great, yet simple upgrade isn't in the technical section yet, it should be.

All you need is a pair of left and right caliper brackets (aka hangers) from an '81 or '82 CB750F or CB900F. The left and right calipers are used on many models of Hondas from that timeframe, but I don't know if the hangers from other models besides the F's will work. There are physical differences, but maybe things still line up the way they should.

From a safety/braking standpoint, this is one of the biggest bangs you'll get for your buck without having to create anything special to make it work. I can't wait to see how the brakes feel once I finish up this project in September.

[Sugs]

Well, if the calipers and hangers fit, does that mean the brake rotors will too? May be more options for aftermarket brake rotors.

[tomk1960]

Well, if the calipers and hangers fit, does that mean the brake rotors will too? May be more options for aftermarket brake rotors.

Yes, the stock rotors fit fine. They're actually very similar to the rotors used on the 81 and 82 CB750F and 900F. They're dimensionally the same, so aftermarket rotors that fit these bikes will fit the GL.

[SnoBrdr]

Well, if the calipers and hangers fit, does that mean the brake rotors will too? May be more options for aftermarket brake rotors.

Yes, the stock rotors fit fine. They're actually very similar to the rotors used on the 81 and 82 CB750F and 900F. They're dimensionally the same, so aftermarket rotors that fit these bikes will fit the GL.

Tried looking on EBay for some, nothing to be found unless I was using the wrong keywords.

[digschopper]

I've been wondering about this. I'm guessing the F master cylinder would complete the swap nicely. I wanted the smaller bore " flat" m.c. anyway for improved feel...

[digschopper]

Tom,did you use F or GL lower brakeline? I want some S.S. braided replacements.

[tomk1960]

I've been wondering about this. I'm guessing the F master cylinder would complete the swap nicely. I wanted the smaller bore " flat" m.c. anyway for improved feel...

I'm using a CB1100F master for this build. Any of the "F" masters will work fine with these calipers. There are others that will too.

Tom,did you use F or GL lower brakeline? I want some S.S. braided replacements.

It looks like the stock length GL lines will work. As soon as my new Galfer SS lines arrive, I will confirm.

I'm a dealer for Galfer and get good pricing. If anyone is interested, I can provide a kitted caliper upgrade that would include new SS lines, powder coated dual piston calipers and hangers, mounting bolts, and rebuilt with K&L pistons and seals and Vesrah pads. Any kits I sell will result in a donation made to NGW.

[desertrefugee]

This is very cool. And the fact that it's been done before is irrelevant. It is not commonly known and I am VERY happy to see this. In fact, it really shouldn't be too much of a surprise. Honda took advantage of economies of scale and shared parts across a lot of models. For instance, the CBX shares the same front rotor as the early GLs. (Early CBX caliper is still single pot, but it gained the twin pistons with the Pro-Link incarnation).

Thanks for bringing this up, Tom. Dang it. Another bit to spend money on...

[Damferg]

A good friend of mine who was a Honda dealer in TX for many years has been watching my progress with my 78 GL. Today he asked me why I was sticking with the stock single piston calipers. He suggested bolting on some dual piston calipers like the ones used on many of the early-to-mid 80's Hondas. I didn't think it was possible, since bolt patterns, geometries, etc. may vary. I wasn't sure that there was a caliper hanger that could bolt right on. Well I'm really happy that I listened to him. When I got home, I grabbed a spare right caliper and hanger from my stock of "F" parts. Guess what - it bolts right on and everything appears to line up perfectly!



Someone here must have done this before - maybe many of our members have? How did I not know this until now? It even looks like the brake lines will be the correct length. Instant brake improvement!

That is just amazing!!! I'll do the swapp ASAP.
Thank you for the info!!!