1980 KZ750H LTD Front master cylinder question

First post here, seems like this is a pretty good place to get some info on my old KZ.

Anyway, I'm working on a 1980 KZ750H (four cylinder) that needs just about everything. Judging by the plate that was on the bike when i bought it, this thing has been sitting since 1989, so I'm sure I'm going to be fighting an uphill battle on this one.

While i'm waiting on some other parts to arrive, I pulled the front brake master cylinder just to check the condition as it appeared the master cylinder was empty. Well aside from the fact i have to clean out what appears to be jello in my master cylinder, I noticed the gasket on the cap was ripped. I have looked a fair bit online (including searching here) but I have not been able to find this part.

Does anyone know if the master cylinder cap gasket is available, and if so, where?

Thanks in advance.

The diaphragm is listed as currently unavailable at Partzilla, so the part is probably NLA at the dealer & everywhere else.
You might be able to find a NOS part on EB, but nowadays the price might be high. DIAPHRAGM 43028-1008
That master cylinder design has a tendency to leak at the cap, so I installed a Honda CBR500 Fr brake master cylinder.
Mine is single disk (1/2" or 12.5mm piston bore), but you'd need to get a dual disk mc (5/8" or 16mm).

No eBay APP ID and/or Cert ID defined in Kunena configurationIf that's the correct part number, this one seems reasonable.

thanks martin_csr for posting the part number! i purchased the mc rebuild kit before i posted this, and i'm not counting on that gasket/seal/diaphragm coming with that kit, but i won't buy the one DOHC posted until i get my kit I ordered. For the time being, i would prefer to keep things relatively stock on this bike, as my main goal is to get it on the road before i go and do any mods whatsoever. With that said, did you have to do any modifications to the switch to make the brake light work with the Honda MC? I purchased a MC off EB that was supposed to work on a kz750 but it was entirely wrong as the switch connector was different and the brake hose attached to the front rather than the side like the stock MC does.

I figure of all the things to cheap out on, brakes probably aren't the thing to do it on. I will keep you guys updated on how things are going.

On a side note, one of the screws in the master cylinder was stripped so I had to use a damaged screw removal tool to get it out. Is there any reason why I shouldn't use the machine head screws available at lowes or home depot for probably 10 cents a piece rather than buying the ones online for 3 or 4 dollars a piece plus shipping? As i said, brakes aren't something to cheap out on, but if i'm just paying for a black machine head screw rather than mill finish, I'm happy to not have the color match if that's the only difference.

The hardware store screws should be fine. The brake hose orientation at the aftermarket mc shouldn't be that problematic with new ss brake lines which should be installed anyway. As for the brake light switch, I got the wires from a late model KZ1000P police bike. It was a direct fit to the bullet connectors inside the headlight bucket, plus the wire colors match. I have a good crimper for making the little wiring pigtail, but since I didn't have all of the needed stuff, it was easier getting the police wire lead assy. In the pic I only used the wire assy, not the police switch.

I just stripped a 81 kz750/4 yesterday engine shot have every part but frame and engine. (Ie front and rear breaks complete lines and all...air suspension swing arm to triple tree bolts and all) starter, stator , drives haft mags rear disc front duel disc...just couldn't see it all get crushefld.. I have 80' 750 twin hardtail. Kinda hoping parts might interchange...NOT..... parts available

As was expected, the diaphragm did not come with the rebuild kit. Just wanted to let you guys know in case anyone else needs this part. Hopefully should do something about getting the MC rebuilt in the next few days and i'll just have to wait on the diaphragm at that point. I have no shortage of things to do on this bike, so it shouldn't hold me up too bad.

On a side note, I'm sure you guys will see me around here more. Thanks again for the help!