Sporadic gas leak

[Petey4]

I've been experiencing a lot of dripping from the overflow tube -- but only every couple of weeks, and under varying conditions. Recently it happened when the tank was nearly empty. Prior to that it only occurred when the tank was nearly full (even though I don't fill past the bar). Yesterday, however, it happened with the tank 2/3 full, but on a pretty cold morning (45 F). So I'm thinking there might be some sort of vacuum occurring, but I can't replicate the conditions enough to bring it to the shop (where, on the phone, they suggested it might be a carburetor problem (!) -- so I'm not feeling very optimistic they know enough about it to recreate the conditions).

Is anyone familiar with this problem? Once it starts dripping it keeps dripping for the whole ride, but seems to correct itself before the next ride. It used to happen every time I filled up, until I learned about respecting the bar in the tank. Now it still happens occasionally, but what could create a constant flow of gas drips from the breather tube when the tank is nearly empty??

[eamartin]

The first thing that comes to mind is a float valve which is not sealed.  Could be debris in the fuel system intermittently catching between the needle tip and the seat.  Second thing is a float that doesn't float. What year is the the bike and how many miles on the odometer?

[Petey4]

It's a 2015 200i -- purchased new last January, so I only have three weeks left on the warranty. Obviously, the shop's suggestion that the problem might be carb-related was misinformed. I'm trying to figure out what conditions could cause a steady drip from the breather tube from an almost empty tank. Doesn't it sound like a vacuum problem?

[eamartin]

In your initial statement you said the gas was dripping from the overflow tube which is the term commonly used to describe the carburetor overflow hose.  But in your last entry you said the gas was coming from the breather tube which I am not familiar with.  Please clarify.  Thanks.

[Stig / Major Tom]

You are leaking gas below the scooter even from a nearly empty fuel tank?

There are 3 hoses up there on the fuel tank.
An overflow hose, a vent hose, and the line taking the fuel to the engine.
There really is no 'breather tube' subject to leaking - just a hose to your sneaker tops if you're standing there over-filling the tank at the gas pump.

THE OVERFLOW HOSE:
OK, the "overflow hose" is connected to the rubber tray which is next to the gas tank opening. It is simply there to drain off, below the scooter, any gas you spill when filling - or if you overflow the tank opening itself. This hose is hard to see if the under-seat bucket has not been lifted out. It is connected on the left side of the rubber cup. (same side the side stand is on)

I doubt you are leaking gas from this hose - opening the seat would show you a puddle of gas sitting in that round black rubber tray, waiting to drain off.

THE VENT HOSE:
This vent hose is the one connected directly to the filler neck, just below the gas cap. It is not meant to have fuel in it, ever. It is NOT an overflow hose.

Since you have a history of overfilling the tank - you likely now have fuel through this hose into the emissions and venting system ( which has a one-way valve and a canister in the system of hoses on the front of the tank - visible when you pull the underseat bucket) This hose/vent system is meant to take the fuel tank vapors to be burned in the engine. I think.
I guess you could have fuel in this system which is now dripping out.
You could remove the seat bucket and study these vent lines - I removed and cleaned mine out one time - getting that valve working again by sucking and blowing. Take a picture of the hoses so you can replace them properly. Shake 'em out, gently blow out any fuel from that acorn sized valve case.
Still, hard to understand how a nearly empty tank could have fuel raised to the tank neck to enter this system?? Is there a vacuum when you open the gas cap, ever? It is meant to inhale - does it? Mine got stopped up one time. I used compressed air to clean it out.

THE FUEL LINE TO THE ENGINE:
This might be the best place to find your fuel leak. Please remove the seat bucket.
 Starting up on the tank, look for a leak from the fuel line connection at the nipple of the fuel pump, down to where the fuel line ends at the injector.
Is the area around the injector wet? The fuel pump is under that silver disc with the 6 golden bolts. Any wetness around that silver cap, or the hose connection?

Yeah, your carb drain isn't leaking - nor is your float stuck. You have fuel injection.
Hope you tank isn't leaking - that would be a first.

Please take a look again - and tell us what you find.

Stig

[Stig / Major Tom]

PS:

You have a 2 year warranty from the date the scooter was first registered for the road....not from the manufacture date. If you are the first owner - you are nearly half way through your warranty.
The warranty is also fully transferable to the next owner.

Stig

[ole two wheels]

I would be interested in knowing if the engine is performing as it should? If you were having an injector problem then the engine should be surging and generally running rough. I think Stig has given you some good pointers. You need to locate the source of the leak. Let us know what you find out.

[eamartin]

No carb? I cannot help.

[Petey4]

Great things to check out, thanks Stig. I didn't know there were separate breather- and overflow-tubes. I have not overfilled the tank in about six months (but ride the bike four or five times a week). Could that still be causing problems?

I think some parts of my warranty end after one year, so I wanted to play it safe. But good to know if this would be covered for two years -- in which case I can study the problem at my leisure.

(Performance has been good -- even when dripping)

The challenge is that the dripping only happens sporadically, so it might take some time to see it when I have time to do some investigating. I guess it could be a gas pump problem, but I would have thought that that would be more consistent. Still, it is hard to imagine a vacuum causing an empty tank to overflow.

Was hoping this was a known issue around here. But I'll learn what I can and report back!

Thanks, Pete

[Petey4]

Solved. Stig was on the right track, but the leak only recently got bad enough that I was able to see what was going on.

The leak was from a loose clamp on the main fuel line. What made it confusing was that the spray from that leak went directly into the overflow pan (under the filler cap) -- making me think some sort of vacuum was pulling the gas up from the tank. Just a coincidence of physics. Tightened the clamp, and all is dry.

[Stig / Major Tom]

Hot dog !!
Your really strange fuel leak was a puzzle!
Hidden hose clamp leak😊
Thanks so much for your "fixed" post.
These LIKE200I's drive trains remain pretty dang bullet proof !
Stig