Leaking gas from the carbs

1981 Seca XJ 550.

The motorcycle was running fine a few weeks ago, but when I went to start it this morning after it had been sitting a few weeks, gas started pouring out of the carburetor.

I gather it's likely related to a stuck float. What I am wondering how likely am I going to need to do a rebuild.

Other than a little touchiness with getting the idle perfect (I live in Colorado not sure if that might have something to do with it), the bike has well for the past five years or so.

 

Sounds like a stuck float or a bad petcock.

 

Not "or."

Definitely a stuck float; maybe ALSO a petcock issue. A leaky petcock alone won't cause it if the floats are functioning properly.

They're not.

You definitely will need to "service" the carbs. The procedure is clearly outlined in both the FSM and the Clymer. Then, based on what you find doing the recommended service, you'll know how much "rebuilding" is truly necessary.

 

Thank you. I would not have thought to check the petcock as well because it looked like it was just coming from the carburetor. I was a little worried about letting it run while it was leaking like it was.

And considering I've been needing to replace the valve cover gasket, I guess this is the time to pull it all apart anyway. I was going to wait till winter since I was told I should check the valve clearances (and the possibility of needing to order shims) while I had the valve cover off.

...and it's a good thing I checked on a thread you were in bigfitz52 because it looks like I better get get some of the donuts for valve cover bolts as well (Pressure Washers?)

Looks like you've helped me out at least twice today.

 

You missed the point.

YOU HAVE A FLOAT ISSUE.

IF there is a petcock issue, it is secondary and at worst, can "enable" a stuck float to allow more fuel through than if the petcock were shutting off.

But that is an "if." What is NOT an "if" is the fact that you have one or more floats that are not shutting off properly.

Further, it the carbs are leaking gas OUT, then they are also probably dumping gas IN-- into your sump.

DO NOT run the motor any more until you check for gasoline in your oil. Open the filler cap, insert nose and have a whiff. If it smells of gasoline the oil is polluted and needs to be changed to prevent damage to the motor.

-You need to service the carbs, as I said. Look in your service manual.
-You will need to bench sync the freshly serviced carbs, and be sure to accurately wet-set their float levels.
-You will need to do a running vacuum sync, with YICS blocked. FOR THAT THE VALVE CLEARANCES NEED TO BE IN SPEC FIRST.

You should have at least checked the valve clearances prior to putting any miles on the bike; depending on mileage and if they were ignored, you could be on the verge of damaging the motor.

 

+1
My most recent XJ project had exhaust valves with 0.04 mm of clearance. That is scary-tight, and I'm surprised that none of the valves were burnt. The single most overlooked maintenance item on motorcycles is setting the valve clearances because people assume that it's either not needed, or too difficult to do (neither assumption is true).

 

When I got my '83 it only had 7100 neglected miles on it, and 7 of 8 were tight. Two were scary tight.

I caught it in time and now it's a textbook healthy mill.

Ignorance is NOT bliss.