1980 750 twin Petcock

Hello folks ,haven't posted in awhile ,haven't had to, the bikes been doin great.It seems its time to get serious and rebuild the Pet cock on the 1980 750 twin.I've sold it to a new rider and I want to help him get it right.I've always been able to find the sweet spot when turning the gas off except every now and then. now the petcock leaks more and more.it's the screw on type and I just want to get the right kit the first time.can anybody help us out on that.Thanks Oljo

From the diagrams at Partzilla for the 1980 750-G1 Ltd II, there's a 10mm o-ring on the lever assy.
Z1Enterprises.com has the 670B2010 o-ring w dimensions & lists a petcock gasket that may be for the sediment cup. ???
A HF metric nitrile o-ring kit may have an o-ring in the correct size or close enough.

Edit: Z1Ent also has a rebuild kit w 4 o-rings/gaskets. Z1Enterprises.com --- petcock kit -- KL18-2712

Thanks for the info.I found a kit at Motorcycle solutions that looks like it might work,According to them the same kit will fit a Z1900 and a KZ1000.Very few parts to it.Do you know the thread size of the nipple on the tank? That would allow us to use about any two feed gravity fed petcock wouldn't it ? If we got the threads right.Just wondering,Thanks again. I'm editing here.I found the oring at z1 by your part number. thanks again ,we will need that one too .Gonna need which ever one stops it from leaking into the carbs.Is that the sediment cup gasket your talking about?

The quote below is in regards to a 78 KZ1000. from the KZR Archives. wg is pretty knowledgeable.
I believe the 750G has the same petcock nut that screws onto the bung.

By wiredgeorge: keep in mind that the bung on your tank is 22mm as is the bung on a Harley tank. They call it 13/16 and it has NPT pipe thread so you can basically use a Harley petcock. Both Drag Specialties and Custom Chrome sell them with 22mm (13/16") threaded nuts...

Z1Enterprises.com --- Pingel dual outlet petcock TU03-0529

Thanks Martin ,that's valuble information that would be very hard to find without this site.