Gas in Crankcase

[Buster]

Anyone ever had gas leak into crankcase.

[RoadKill]

Gas in the crank case could be just a build up over time of unburnt fuel from an over rich condition or it can leak at the petcock into the vacuum line filling the cylinder and leaking past the piston into the crank case. either way it is a bad situation and needs addressed IMMEDIATELY before damage is done.

What are the symptoms/indicators you noticed ? Why do you think it's gas in the crankcase? 

[asfltdncr]

Maybe some of the other members can chime in but would this not be the same cause and solution as a case of hydrolock with the petcock not shutting off and one or more of the carbs have a needle valve issue.

Also, have you drained the tubing underneathe your bike with the plastic plug in it.  I believe it is supposed to catch condensation from you crankcase and if you don't drain it (every oil change), it could back up into your crankcase.

Good luck and wait for some of the more knowledgeable and helpful members to answer this for I have not experienced this yet, myself.

[¿spoom]

It's not uncommon on carbed bikes. If you have a carb that leaks past the float's needle (or the float sticks, etc.) and that carb's intake valve happens to be open, gas can leak into the cylinder and past the rings. Our bikes have vacuum petcocks that are only supposed to flow when the bike is running and engine vacuum opens the petcock diaphragm. The oil needs to be changed, but obviously you'll need to track down the means of entry in the first place.