'77 KZ-1000A-1 Fuel Tap Question

For anyone familiar with the '77 KZ-1000 fuel tap I have a question. It appears that this is almost a two piece unit in that it has right hand threads to screw the locking nut onto the fuel tank outlet and left hand threads to screw the petcock into the locking nut. Mine has developed a leak and it is not the diaphragm. It seems to be coming from the locknut. My question is, do you thread the locknut onto the fuel tank outlet first and then tighten it before threading the petcock into the nut or do you thread the petcock into the locking nut and tighten it and then thread it onto the fuel tank outlet? It seems as though you have to work both ends against a single o-ring in order to get an effective seal and I am not getting that seal. I may have a bad locking nut because as I tighten it up it seems to want to slip on the fuel tank threads, but it does seem to get pretty tight if I screw the nut onto the fuel tank outlet by itself. Does anyone have an idea of what the thread size is on the fuel tank outlet?

Rick H.

Pretty sure it’s 22mm

I’ve threaded the nut into the petcock till it lightly seats. Install the O-Ring and then the complete petcock spun onto the tank bung, clock the petcock and tighten the nut. I’ve had to move the nut to get the O-Ring to seat against the bung and clocked correctly. Just play with it and Ta-Dah it ‘s done.

You can go diffrent ways to to put the petcock/gasket on. The Petcock nut has both LH on Petcock/RH threads on tank. The Goal is to tight fit all parts together,(tank/gasket/petcock outlet position), in the middle of the nut area.

I ordered a new gasket/0-ring for the gas tap and when I tried to install the petcock on the tank I noticed that the threads on the lock nut literally slide over the threads on the gas tap. Unless my guess is wrong, this can't possibly be the correct way this thing should go together. As you tighten the locknut up the petcock threads simply slip thru the threads of the locknut. Has anyone ever run into something like this? The locknut will thread onto the fuel pipe outlet on the tank, but not so for the locknut on the gas tap. If I didn't know better I would say this petcock was an aftermarket replacement and not a very good one at that. There are no markings on the petcock to indicate who made it. Does anyone know the correct part number for a Pingle replacement valve for this bike? I may go that route rather than putz around with the mystery valve I have now. Thanks in advance for any help on this.
Rick H.

I found Redline having the best price. I just upgraded to a single outlet Pingle from Jim

So a wee bit more investigation was required on my gas tap issue to find out the problem. I ordered the OEM gaskets and a new OEM locking ring. The OEM gaskets aren't even close to the correct size for my fuel tap and are much smaller. The new locking nut would only turn onto my fuel pipe about 1 turn and would jam tight. Looking at the fuel pipe off the gas tank closely it appears someone at one time had put something like JB Weld on the threads as a filler/repair substance. This caused the old lock nut threads to ride over the JB Weld material and deformed the threads on the nut. I cleaned the filler substance off as best as I could and am now waiting on a 22X1 mm threading die so I can clean up the threads on the fuel pipe which are not in the best of shape. It also appears that the threads on the locknut have been distorted due to overtightening on the fuel tap. All this indicates to me a previous owner made a misguided attempt to repair a gas leak and installed a cheapo fuel tap which was overtightened and slobbered into place. Just goes to show how something so simple can be made into a much bigger problem when good intentions go a stray.
Rick H.