Rebuilding the front master cylinder.

I am ready to rebuild the front master cylinder on my 1976 KZ900.
My Clymer book does not go into details on this process.
Any help would be greatly appreciated.

im not sure about the 900, but when i rebuilt mine for my 750 it was super easy. it took about 10 minutes to do it.

MTH76 wrote: I am ready to rebuild the front master cylinder on my 1976 KZ900.
My Clymer book does not go into details on this process.
Any help would be greatly appreciated.

There is a internal snap ring that is hard to remove. I bought a pliers but it did not really help.I ended up getting it out with tiny drill bits.Just check the inside of the master cylinder as there are two holes in the bottom , take a fine wire and make sure both are clear of rust . My 1976 Kz 750 would tighten up the brake while I was riding. The smaller hole was blocked not letting brake fluid return to the master cylinder after braking. It would actually tighten up even if i did not use the brake at all.

Mine was all rusted out, the circlip was rusted on solid. Got it out by using Marvel Mystery Oil followed by the torch on the outside of the cylinder body in the area of the clip. Then used an appropriately angled pick to to grab one of the holes on the circlip (the other hole was all rust and melted away) and pulled on it until inward and up at the same time until it came out. Had to be careful not to snap/break the circlip. Here's what I found.



I rebulit the calipar at the same time and flushed the lines.

For FSM in KZr's FILEBASE,
click > www.kzrider.com/filebase/doc_download/43...asaki-service-manual

Good Fortune!

Yes, Is it old? Yes. And alot of miles? Yes. Do you plan on re-building it???
We'll seeing that OEM started with DOT 3 brake fluid, which retains moisture, the aluminum bore is most likely pitted and corroded! Did yours seep fluid? Yes!

But, you need to pull off that rubber seal covering the brake lever. then you need to have a set of snap ring pliers, to get down about an inch and pull out the snap ring. Then the guts will come out. Then you will see the bore after you clean it out. It will be pitted.

So, either bore it out to 5/8ths and get that rebuild kit. Or waste $30 bucks on the smaller 14mm single disc kit and waste that money. Because it will still seep and leak fluid. 90% of the time.
I have went through this 10 times in the past.

I would just buy an aftermarket retro fit round master cylinder for $129, from the foriegn imports. That's if you want the same look.

But if you are broke like most of us, once you get the guts out. Then you can bore your cyl. out with scotch - fine (gray) cloth or wet sand with 400-600 wet sand paper on a drill motor. Boring it like a piston cylinder block.

Then with the new rubber parts, you might tighten it up a little. Just don't have a new gas tank paint job. Cause it will drip eventually. Just My Opinion!

Good Luck

Thanks to everyone,you are a great help!
I will try to get this started this week.