Motorcycle Repair: Yamaha leaking gas, gas tank, air filter

Question
I have a 1978 Yamaha 750XS and I opened the gas tank to see how much fuel was left when gas started pouring out above where the air filter sits. If I leave the bike standing straight up it doesnt leak

Answer
Hi Fred.
 The answer to your problem is simple.

The floats are sticking while the bike is in a lean.  Take the carbs off and check the float mechanism.  Something must be slightly loose.  It happens over the years with bikes that old.

Good luck.
FALCON