Rough Idle, Some Smoking, Gasoline Dripping on First Run This Year

Hi,

My 1991 ST1100, with 55K miles, has been trouble-free the past 4 years, but I got the bike out today and ran it for a while, and noticed gasoline dripping under engine. I pulled the seat and covers off, and noticed dripping just below the air chamber/duct assembly towards the front of the bike. I have never removed the carbs. Do they come out as an assembly, or do I disassemble the air chamber/duct assembly and deal with each carb individually?

From the dripping and the smoke coming from the right side exhaust, I am guessing the #2 Carb has a stuck needle and seat, and is flooding. Usually, I will run the bike for 15 minutes each month, but I was not able to do so this year, and now I am paying for it.

Any suggestions/help would be appreciated.

Seth Anderson
Moon, VA

1991 ST1100
1990 PC800
2012 NC700X

I would look at the vacuum fuel shutoff valve first. The diaphragm can leak and dump fuel into the intake through the vacuum hose connected to it. Since you have smoke on the right side this could be the problem.

The vacuum fuel shutoff valve is on the right side, attached to the bottom part of the air filter housing. About where your right knee would rest. If it is leaking, the gas could be running down wires or hoses and end up anywhere. You can remove the vacuum valve for "testing". Just remember to plug the vac. line. Best to get a gas leak fixed now rather than latter.