KZ 750 petcock

The petcock on my KZ was not working and dumped fuel into my crankcase, thanks to this forum I found a great parts place and put the new diaphram in today. I have not put the tank back on the bike yet because I had a small amount of fuel left in the tank and this was leaking out of the gas line hose. I made sure that it was not on prime but it still leaked. Does the tank have to be all hooked up to make the vacuum work and stop the flow? Or have I not put it together correctly?

If vacuum is NOT applied to the diaphragm, then gas should NOT come out the gas spigot. I suggest you buy a Pingel adapter plate and get a gravity petcock that has a positive fuel cut off in the OFF position. Change your oil as that gas went somewhere when it flooded your combustion chamber.

del

1982 KZ 750 R. I got the kit from Z1 enterprises and it looks identical.It appears to be a good quality kit and they were very helpful and knowledgable.I have changed out the oil and cleaned the filter and it all looks good. I am assuming that it should not leak even when the tank is off the bike, correct?

del

I will try that and see what happens. Many thanks,GGJB.

wiredgeorge wrote:I recently purchased a rusted but salvagable 1978 kz750b3. It has the stock PC rusted to the tank and a new replacement PC in a box of loose spare parts. Both are vacuum operated. I know from experience that the older vacuum pets are pretty much junk. My yammi xs750f is imfamous for gas/oil from leaky PCs. On that bike i replaced with stock gravity fed PCs from an xs650. Question is: what would be a good gravity fed PC that, along with a pringle adapter, would work the best with the kz750? Any ideas would be appreciated.

If vacuum is NOT applied to the diaphragm, then gas should NOT come out the gas spigot. I suggest you buy a Pingel adapter plate and get a gravity petcock that has a positive fuel cut off in the OFF position. Change your oil as that gas went somewhere when it flooded your combustion chamber.

oops...actually i wrote that last missive, not wiredgeorge...

I bought a Suzuki diaphram petcock after messing with mine for too long unable to get a replacement. Works!

Lots of options out there. (Sorry purists....)