First post, first bike even. 1980 xs650 special with less than 5k on the odometer. Not sure if true, but I think it is. Here is my question: so I thought I had battery problems when I first bought the bike; it would stall out after a few minutes of starting. I could go about a 1/4 mile then it would bog down and die. Anyway, got multimeter and checked the charging of the battery and it was good. Next, invited father in law over (ex motorcycle mechanic) and he discovered it was the petcock with no vacuum on it. As I am told, the carbs have the vacuum connected between the two (aftermarket). So when I want to ride, I set my petcocks to primary and everything is good. When I park the bike, I set the petcock to ON for the lack of flow (no vacuum). Is this normal? So far it has worked for me.