I just picked up an ´83 750 Seca for free. I have no experience with motorcycle repair at all and figured this would be a fun project. Could someone tell me the function of the fuel petcock valve. What is the difference between On, Res, and Pri? Right now, when it is in Pri, fuel pours out the bottom of the bike. It drips out when it is running in On, and it doesn´t come out at all in Res.