Brake Master Cylinder

So, as per usual I did something stupid and fixed my 1977 KZ400 until it broke. I broke my master cylinder beyond repair so I went down to the local junk yard and picked one that looked similar from a basket of parts. I need to buy a rebuild kit for the Master Cylinder I purchased but I have no idea what bike it came off of originally. I'm hoping the very helpful KZ community might be able to help me out. As you can see in the pictures it is all metal, suggesting 1970's and since whatever bike it came off of had a front disc brake my guess is that it is from the late 1970's. The black tip where the brake hose attaches would seem to be unique to whatever model it came off of. Any help is much appreciated.



First Picture is of the gf and I's KZ400's. The rest of the pictures are the master cylinder.

Try pulling the piston and seals out, then measure the bore diameter. Post up pictures of the piston assy, and the length, also bore dia. That might help.