Front brake/disc conversion

I'm trying to research a front brake conversion for a 77 kz650b. I've come across a good thread here using the newer ex500 calipers. kzrider.com/component/option,com_joomlab...,5/id,120955/#120955 .

Then I got to thinking about making an adapter for using a different disc. One idea was to use a simple thick piece of aluminum billet to bolt to my 4 holed hub and drill/tap it to bolt on a disc from a zxr1200 which appears to have an offset (less of an offset than a kz) already incorporated bewtween the mounting plate and the braking disc.

My other idea, was the possibility of maching a solid mounting plate that could be designed to take any number of bolting patterns of discs with no offset.

What do you guys think? Is this a reasonable approach?

zippywhoosh wrote:

I'm trying to research a front brake conversion for a 77 kz650b. I've come across a good thread here using the newer ex500 calipers. kzrider.com/component/option,com_joomlab...,5/id,120955/#120955 .

Then I got to thinking about making an adapter for using a different disc. One idea was to use a simple thick piece of aluminum billet to bolt to my 4 holed hub and drill/tap it to bolt on a disc from a zxr1200 which appears to have an offset (less of an offset than a kz) already incorporated bewtween the mounting plate and the braking disc.

My other idea, was the possibility of maching a solid mounting plate that could be designed to take any number of bolting patterns of discs with no offset.

What do you guys think? Is this a reasonable approach?

I'd leave your wheel and rotor setup alone, and look at how to get your new cailper to mount up to your fork leg. Brake parts have to handle enormous stress so you'll want ot be careful what type of materials you use to prevent failures.

If you're machine has one disc then the dual conversion will help a lot and the engineering behind it has been done by Kawasaki already(most if not all front wheels are already tapped for the second disc.) But it does add unsprung weight and will make the front end feel a little heavier.

Your highest performacne option is probably a lighter rotor (EBC has a drilled one that fits) and a twin pot caliper. Machining brackets athat are safe isn't easy. Grimeca mad a fancy kit for the KZ thats still available, from Klasmo I believe. Sure its pricey, but I feel brakes are worth it. Besides it looks *really* cool!

Hope this helps...Sam

PS: I've done the dual disc conversion on my kz1000 and so far so good.

I've been doing these type of conversions for years with newer discs and newer calipers.
Fish

Fish; (then Sam)

Now that is what I'm talking about. I'm looking at some first generation sv650 calipers and dics to work on a kz650 spoked wheel. The two pot calpiers look like they may fit. They need to be good and narrow for the bit on the inner side of the disc so as not to clip the spokes.

Do you have any experience doing a caliper rotor conversion for a spoked wheel. The first generation sv650 rotors look like they have a decent offset, but I'm having a bit of a time getting the actual measurement.

Any insight you may have would help.
Many thanks


Sam;
Thanks for the input. I'll check with EBC regarding their rotors and two pot calipers. Sounds like a new/proper fix for an old problem.

Cheers
Scott

The twin piston calipers with both pistons on the outside usually work best for the spoked wheels. Apposing piston calipers can interfere with the spokes. I have made a few that use the stock rotors with newer calipers, but the newer calipers are usually made/fit better with the newer,thinner discs.
I have a mill / lathe and it makes doing these conversions alot easier.
Heres a few pics of the kits I have made.
Fish

GL 1000 Goldwing front forks

Fish

What you've done is pretty close to what I'm thinking. I'm waiting for the arrival of a first generation SV650 set of rotors. They have an offset smaller but similar to the rotor on the 77 kz650 I have. With the offset, it provides more clearance from the spokes. Also the slightly larger rotor diameter moves the caliper further from the hub and also increases clearance to the spokes.

As for the caliper I've also gone the way of the first generation sv650: 2 pot (non opposing pistons) These calipers appear to have very little caliper that lives on the inside of the rotor. Again spoke clearance hopefully won't be an issue.

Not having a lathe or milling machine I am going to have to get a local shop to help me out with the bracket for the fork/caliper connection. Also the new rotor to the old hub is going to need an adaptor of sorts. What do you think of a 1/4 inch (or so) disc drilled to bolt onto the hub (4 bolt pattern)as per the original rotor and then tapped to receive the new rotor (5 bolt pattern. Seem reasonable?

Cheers

zippywhoosh wrote:

Fish


What do you think of a 1/4 inch (or so) disc drilled to bolt onto the hub (4 bolt pattern)as per the original rotor and then tapped to receive the new rotor (5 bolt pattern. Seem reasonable?

Cheers

If you look closely at the forks in the bottom picture, you will see that the discs has an aluminum spacer at the disc mounting bolts. This is used to center the disc and to mount the disc. The inside of the spacer adapts the Honda hub diameter(62mm) to the larger disc carrier (I forget- larger than 62mm).
The top picture(6 piston-tokico) has discs that have the center machined out to fit the Honda 62mm hub.
The very top picture (Kawa front end) has 6 bolt discs that were redrilled to the 4 bolt Kawa disc bolt pattern. Works fine and looks better with the stock covers (for the disc bolts)
If you will be using a newer disc with the big hole in the disc carrier (Most newer sportbikes) than an adaptor with the Kawa bolt pattern to the larger sportbike disc carrier hole would work fine. If your disc has a smaller sized center hole in the carrier (simular to the stock KZ hub size) then you would probably just have to redrill the disc to the Kawa 4 bolt pattern.I would use a centering spacer to center it (like in the pic).
Theres a bunch of different ways to do the same thing when it comes to this stuff.
Fish