Was wondering if anyone has had the problem I am having.
1994 Wide glide with 42mm mikuni, bike runs ok but after shutting it down and turning off the gas it leaks gas out the overflow, not right away but like ten minutes later. replaced the needle and seat but it still does it.
If anyone has any thoughts it would be appreciated....

 

No real Mik experience really, but is engine heat heating it up enough to push it out after it is off and sitting? There really shouldn't be anything making it overflow if it isn't float related and doing it right away on the kickstand.

I'm guessing the petcock is 100% on it?

Griz

 

It is the needle and seat. Petcock has nothing to do with it, the carb should shut the fuel off to the float bowl.

 

I have the same setup on mine. Once in a blue moon, it will weep a bit of gas out the overflow tube, just as you say. It comes and goes. It's most likely a bit of dirt stuck between the float needle and seat. You don't say what you're running for a petcock, but my Pingel has a very poor (IMO) filter on it- looks like a piece of somebody's window screen-stops nothing. With the leak at the float needle, the remaining fuel in the line flows down into the float bowl, flooding it. It happens slowly, that's why the ten minute lag between shutoff and leak. That's also why it doesn't keep running until the tank is dry-the gas is shut off at the petcock.

Mine's done this once in a while since I've had the carb. It usually fixes itself when the bit of dirt passes through.

 

My 48mm does the same thing brand new, kinda wrote it off as heat expansion, but a little laziness too that i havent pulled the carb and checked the float level. Its only a few drips on mine shortly after riding with the tank valve closed.

 

The standard tip for cleaning the needle on the road - and this happens - is to get it up to speed and turn the fuel to OFF run it right dry, than with the acc pump after turning the petcock back on keep it running - that will flush the complete system doing it twice cant hurt

 

If it just drips for a little while it could be heat expansion, or your float level could be on the high side, then leaning the bike would cause drips to come out of the overflow. If it drips continually then your petcock may not be completely shutting off. If it drips for a while then shuts off it's the fuel in the fuel line getting past the needle and seat. Do you have a fuel filter in the line???? If not get a clear one so you can see if the fuel is staying put. Hope this helps.
John

 

I haven't had the issue the OP mentioned, but I did have a float adjustment issue with my Mikuni this year.

I installed the SE carb ~15 years ago and it was trouble free up until this year. When I rolled it out this spring and turn the gas on fuel was dumping out the overflow, obviously from a stuck float.

When I dropped the bowl to clean the needle, I found that the float was way out of adjustment, and was barely able to close off the flow. That was a major cause of the issue.

I would advise anyone who drops the bowl on theirs to check the float level. I was surprised to see it so far off coming from the factory.

 

We check the float levels as a precaution even on new ones!! Lots of them are out of the range where we like to see them.

John

 

That's me sitting in my buddy's driveway with Smoochie's Mikuni in my hands trying to figure out why it'll leak down and hydraulic a cylinder if I don't shut off the petcock.

I am feeling your pain. Carb runs great, otherwise.

So I shut off my petcock. 8)