1980 KZ750E brake caliper upgrade

I have calipers that are frozen on my 1980 KZ750 4cyl, it has the dual front brakes already. Does anyone know if there is an easy upgrade for this bike? Or other calipers that will directly bolt on? Having a hard time finding oem replacements.

You don't need new calipers, you just need to service the ones you have.

Use compressed air and blow out the pistons. Then inspect the pistons carefully for pitting. Likely the pistons will be pitted so budget money for new pistons and seals. This is not a difficult project, but often people shortcut the process which is not advised. Add new brake lines into the budget and inspect the master for bore pitting too. This all sounds like a lot to do but it's necessary and not difficult. Taking this path will get your brakes working as good as new. Purchasing some used calipers is not advised unless you plan on taking them all apart as well. At the end of the day that will likely cost you more money than just servicing the calipers you have. The photo below shows my 750 calipers after I did all mentioned plus repainted them with gunkote. Good fun.

I have tried to rebuild the ones I have, the bike sat in a field for at least 15 years before I got it. The calipers are very frozen! I was able to get the rear apart using compressed air but no luck on the fronts. One has a broken off bleed screw not sure if an easy out will work on it. Pretty rough shape...

Try doing it by using the brake itself without the rotors on.
Steve

They look amazing, how is the paint holding up? I was thinking of powder coating mine if I can ever get them apart.

Gun Kote is nicer than powder for calipers because it is completely unaffected by solvents. As far as i know its the only high heat paint that ACTUALLY does this. You can shoot brake cleaner straight on it and it will not affect it. Try soaking the whole caliper in a 50/50 mic of ATF and acetone to free up the piston. that stuff is gold. if they are that bad, chances are you will have to buy new pistons due to pitting/corrosion/etc

jcs027fly wrote: They look amazing, how is the paint holding up? I was thinking of powder coating mine if I can ever get them apart.

Sadly, the bike is not running yet! Got the chassis together though. Going through the engine!

I really like the Gunkote. Used it on my wheels too. Kind of wish I'd done the engine as well but used VHT. At any rate, I recommend it. It sprays nicely. You need a spotlessly clean substrate before application. The rougher the better for adhesion. The coating is really fragile before it's baked. Gotta handle the parts carefully and bake right away.

jcs027fly wrote: I have calipers that are frozen on my 1980 KZ750 4cyl, it has the dual front brakes already. Does anyone know if there is an easy upgrade for this bike? Or other calipers that will directly bolt on? Having a hard time finding oem replacements.

I am very interested in this upgrade, as well. I am going through a 1980 E1. Looking for better calipers,and rotors.I will follow this with interest, and post if I find anything

It is puzzling that the 750r1 has 260mm front discs, the 550 has 270mm and the gpz11b2 has 280mm discs for the 7 spoke wheel. Bigger discs will fit just not sure about the caliper mountings.

If you like the later 3 spoke cast wheels with slightly wider rims, my yellow 550 has a 750 uni front end, with 280mm discs and calipers (from 1100 and turbo models) and an 18" 750 rear.

I have got to good front brakes calipers now, need to find a back one now. I managed thru a fair amount of persuasion to disassemble the rear master cylinder, but it has a lot of pitting in the cast and not sure if it is worth wasting a rebuild kit on it. I will try to get a pic on here but I think it will probably leak. Anyone got a decent rear brake caliper they want to sell?