Topic: cyl #3 leaking gas

[79TBird]

took my bike to get inspected Monday and the tech inspecting it pointed out a puddle forming under the pipe, after getting the bike home i see its leaking gas out of Cly #3 at the head/header  joint and running out the pipe.
the bike ran fine till i put new plugs in runs alot smother and stronger now.
pulled the plug and rested it on the head, nice blue spark.
bike started while doing this sprayed air/fuel about foot so im gonna guess its got compresion and didn't seem to run any different then with the plug in.
plug is starting to turn black but is VERY wet.
Is it possible for the timing to be off on just one cyl?
its bad enough that by the time its warmed up in the morning there is a 8+ inch puddle of gas/carbon under the bike.

Thanks
  Derek

[Gordon]

Sounds like a carb problem to me.  Possibly the combination of a couple of things.  Stuck float valve/float level too high, combined with a clogged overflow standpipe/tube.  This would cause the float chamber to overflow, but with the standpipe clogged, the only place for the gas to go is into the cylinder. 

Check that you can blow air through the overflow tube, check the float level heigt, and remove and clean the float valve.  Also, check to see if your oil smells like gasoline.  If gas has overflowed into the crankcase, you'll destroy the main bearings.