Motorcycle Repair: Gas Leak, yamaha xs650, petcock


Question
I just bought a Yamaha XS650 83' from a motorcycle fanatic that
kept it in superb condition.  Pretty much everything was in new
condition on the bike, and it never gave me problems for about
three weeks. Last night i rode it to the store, when I walked
back to the bike there was a large gas puddle under my bike. I
freaked out because I wasn't sure if it was mine and I know I
didn't ride over anything or scrape the bottom. When I drove off
I was certain it was my bike that leaked because i ran out of gas.
Pushed it to the gas station and put a gallon in just in case, and
the gas just started streaming out of the bottom of my engine. I
don't know where to start. Can you recommend anything?
TY
Sitara
p.s. does the throttle have anything to do with it?

Answer
I usually only answer questions on Harleys, but I think I can help. First turn your petcock to the off position. now pour some gas in. if you have a leak then its either the tank itself or the petcock.
If it doesnt, turn the petcock to the reserve position. If it leaks, then your carb float is probably stuck and the carb will have to be removed to clean. If the float is stuck, sometimes you can bang on it with a hanedle of a screwdriver and that will unstick it. If not hten its going to have ot be removed.
Good luck and happy riding
Mike