Motorcycle Repair: carburators and oil, vent tube, carburators

Question
I have a FLHTCU 1991 Harley.  When I start my bike it sucks oil up out of the base and fills the carburetor.  Why is it doing this?

Answer
Your problem is that the oil in the oil tank is weeping into the bottom end. There is a ball on a spring in the oil pump that is suppose to stop that from happening, but I have seen many harleys with this problem. Whe the bottom end of the motor gets to much oil and you start the bike, the oil pump cant pump out fast enough, so it comes out the vent tube. The ball sometimes gets dirt or carbon and keeps it from closing all the way. You can remove it and check it. Also, where the vent tube goes into the carb, you can remove it and locate the fitting under the bike and turn it 90 degrees and let the oil vent to the ground.
Good luck and happy riding
Mike