Topic: Will CB550 brake calipers/holders fit on CB750 K1 forks?

[DesertKyorugi]

I know the CB550 brake rotors are smaller but I managed to find a pair of cast iron CB550 brake rotors that I would like to fit on my K1 if possible. I have read bits and pieces of the CB750 brake being an upgrade for CB550 by being larger diameter but no mentioning of fitment for the early CB750 forks. What year CB550 brake calipers and holders should I look for to fit early CB750 forks? Thanks

[Scott S]

 The 550 caliper holders will bolt right up to the 750 forks. The "arm" is shorter to match the 550 rotors.

[scottly]

K0-K2 750 forks used a different "C" shape caliper mounting bracket instead of the "T" shape bracket used on K3 and up 750s and 550s.
 

[DesertKyorugi]

K0-K2 750 forks used a different "C" shape caliper mounting bracket instead of the "T" shape bracket used on K3 and up 750s and 550s.

So..... I need K0-K2 CB550 caliper mounting brackets?? Or you are saying I need the newer CB750 K3 and up forks to mount the CB550 brackets?

OR I just need the shorter CB550 holder arms to mount on my C shape brackets?

[scottly]

Only the K0-K2 750s used the "C" type brackets; all the 500/550, and 350/400 used the "T" type bracket. Yes, in order to fit 550 brake parts, you will need K3-up 750 forks.

[DesertKyorugi]

Only the K0-K2 750s used the "C" type brackets; all the 500/550, and 350/400 used the "T" type bracket. Yes, in order to fit 550 brake parts, you will need K3-up 750 forks.

Thanks. I wonder if I can just use the shorter arms. I know the arm for the CB750 T type is already shorter than the C type.

I have a set of K3-up forks but it wasn't rebuilt already  My K1 forks are all polished up and rebuilt, ready to roll.

[scottly]

No, you can't fit the 550 arms onto the K1 forks using the "C" brackets. Also, if you want to use dual brakes on the K1 forks, you will either have to modify the stock left-side bracket to fit on the right side, or try to find an aftermarket CFC magnesium right-side bracket like in the pic I posted. (Good luck finding one, as they are as rare as unicorn poop. ) You might be better off trying to find a set of 750 iron rotors? I have a set, but they should be resurfaced/ground, and I'm a bit proud of them.  

[scottly]

The 550 arm mounts the caliper lower than the later 750 arm to account for the smaller diameter rotor.

[bryanj]

Bolt hole spacing is different 500 to 750

[DesertKyorugi]

No, you can't fit the 550 arms onto the K1 forks using the "C" brackets. Also, if you want to use dual brakes on the K1 forks, you will either have to modify the stock left-side bracket to fit on the right side, or try to find an aftermarket CFC magnesium right-side bracket like in the pic I posted. (Good luck finding one, as they are as rare as unicorn poop. ) You might be better off trying to find a set of 750 iron rotors? I have a set, but they should be resurfaced/ground, and I'm a bit proud of them.

Yes, I already have a dual brakes set up on my Valley Green K1. We are restoring the JDM K1 and have all the parts except for drilled rotors. Came across the cast iron CB550 rotors and hence thinking about frankensteining it.

@scottly Would you be willing to sell your CB750 cast iron brake rotors? 

[scottly]

Maybe.. These do have some sentimental value to me, as they were fitted to my bike when I got it in 1979, as well as being somewhat rare vintage aftermarket parts. I also have the caliper which had been converted for the right side brake line and it's arm, but the CFC bracket is now in Canada.
 

[DesertKyorugi]

Maybe.. These do have some sentimental value to me, as they were fitted to my bike when I got it in 1979, as well as being somewhat rare vintage aftermarket parts. I also have the caliper which had been converted for the right side brake line and it's arm, but the CFC bracket is now in Canada.
 

Very nice. It wasn't hard taking measurements and cutting down the bracket. Just have to be careful when shaving the one mounting hole so as not to take off too much. I use 1/2 inch aluminum spacer to mount mine.

[DesertKyorugi]

As it turns out, the K0's brake was doctored. The C bracket was mated to a T arm and a hole was drilled for the spring screw 

[Ricky_Racer]

DesertKyorugi, if you're coming to visit, I have one of the magnesium CFC brackets if you want to measure it against your cut down mount.

RR

[newday777]

DesertKyorugi, if you're coming to visit, I have one of the magnesium CFC brackets if you want to measure it against your cut down mount.

RR

Are you Ted?

Stu

[Ricky_Racer]

Yes, Stu. Have been forever!

Ted

[DesertKyorugi]

DesertKyorugi, if you're coming to visit, I have one of the magnesium CFC brackets if you want to measure it against your cut down mount.

RR

RR, My bracket should be good. I did it the same way as the last bracket that is on the Green Hornet

And yes, I am planning to visit for a parts haul for the K0. I should have most of the parts you need, still digging through my pile 

[scottly]

DesertKyorugi, if you're coming to visit, I have one of the magnesium CFC brackets if you want to measure it against your cut down mount.

RR

Ted, are you aware the CFC bracket was intended to be used with the stock fender brace? If used without the brace, like my PO did, the caliper will be cocked slightly, so washers the same thickness as the brace should be used on those two bolts.

[Ricky_Racer]

Yes I am, Scottly. I'm using the bracket on a set of NOS 38mm Marzocchi forks that are identical to the '69-'72 CB750 forks including the rhino horn triple, except scaled larger overall. The forks were made for Japauto back in the day, and accept the CB750 brake assemblies and front axle. The only difference is that they have no provision for lower fender to fork braces. I'm using an stock CB750 fender brace with a fiberglass fender. I also found a set of NOS JPX Japauto wheels like the ones pictured.

The forks are identical to the front forks on this Japauto...

RR

[scottly]

That, IMHO, is about the homeliest fairing I've ever seen; it looks like a catfish sucking air.

[Ricky_Racer]

Yeah, but it won the 1972 Bol d'or for Japauto. The tank has flared sides for the rider to lay his arms on and the fairing completely protects him. A lot of people hate the look but I think it's kinda #$%*in' and certainly distinctive!

However, it would cost an arm and a leg to buy one and ship it from France so I'm probably gonna have to have an open bike... At least I have an original Japauto tank and seat.

RR

[scottly]

Well, I have to grant you that it is distinctive, if not ugly as a mud fence.

[Ricky_Racer]

Frankly Scottly, a lot of riders didn't like the fairing because it is so big that they couldn't judge where their front wheel was.

I have mixed feelings about using it (assuming I could even afford it!) but it's so trick I'd be tempted if I had one.

RR

[scottly]

I found that with the cheap Viper fairing, I couldn't see the front wheel when loading the bike on the dyno, which made it hard to line the wheel up in the chock.