replacement petcock?

My bike leaked about 6 bucks worth of gass all over and i traced it back to the petcock. I pulled it appart and there are holes all over the diaphram. my diaphram just happens to be circular too, and i guess that didn't come on a 78' kz of any kind so i was told...is there any one aftermarket replacment that everyone uses? Thanks, Louis

pengel adapter and generic on/off petcock from z1enterprizes.com

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