for motorcycle petcock

l dont know but it got me hot reading that word.

A petcock was/is originally a valve for releasing the pressure of a steam engine or a drainage valve.
The etymology seems to be from cock (as in cockerel) based on the shape of a cock is head resembling the valve shape (also used in stopcock) & pet is an obsolete term for breaking wind.

EDIT: the stupid filter has changed the word to asterisks – how small-minded is that, it is the bloody English language who is going to have their eyes burnt out by reading xxcockxx?

a valve that directs the fluid, l guess they could have otherwise called it prostate?

A young man once had a small chicken as a pet. He needed help with stopping the flow of liquid from the kettle he was making stew with. There was nothing around him except is petcock so he shoved the chicken into the kettle which in turn stopped the leak. He in vented chicken stew and petcock all at the same time.

Pet - petrol
Cock - a type of valve or faucet
Petcock - petrol valve