The threading is m16 x 1.5. But the petcock nipple is only 3/16 and is waaay smaller than the fuel inlet nipple on the carbs. I have to crank the line on with a hose clamp and hope it doesn't leak or use too small of fuel line and risk choking it for gas or splitting/leaking at the carb inlet.
Temporarily my workaround fix for that was using a small piece of 1/4 inch fuel resistant hose over the nozzle which I slid the larger fuel line over. Worked well enough but it's not the solution I want permanently.
Sorry btw for making you zoom to see it, it's the only pic I have of it and I'm not with the bike.
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