4T Leaking Gas Into Air Filter Box

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Wild Handyman
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4T Leaking Gas Into Air Filter Box

Post by Wild Handyman »

I'm sure this issue has been covered before in this forum, but I can't find it. My 2012 Stella 4T (w/ 600 miles) is leaking gas from the mouth of the carburetor whenever the fuel selector switch is turned on. If the selector is left on when the bike is off the air filter becomes completely saturated with gasoline, the gas puddles on the floor and the bike will not start. When the bike is running and I blip the throttle I can see a little gas spitting out of the carburetor. I'm sure the problem is inside the carb somewhere but I don't know exactly what I should be looking for. My closest Genuine dealer is over two hours away in Richmond, VA so I will probably have to fix this mess myself.

Note: I just replaced the gas line from the tank because the line was kinked from the factory & also installed a new fuel filter. Is there no quality control at LML?
Yalzin
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Post by Yalzin »

"It's not a bug, it's a feature!"

...is what all Stella Owners tell themselves as they work on their bikes.

Is your needle valve/float stuck?
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Wild Handyman
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Post by Wild Handyman »

Yalzin, the float bowl pin could have been it as the tip seemed filmed with dirt. I disassemble the carburetor, cleaned everything, put it back together and as soon as I started the still-leaking-from-the-carburetor scooter, with the normal attendant vibrations, the leak stopped and the scoot seems to be running normally. I believe the vibrations re-seated the newly cleaned float bowl pin. Now to go for a test ride to see if it really runs correctly.
dasscooter
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Post by dasscooter »

If it comes back, you can polish the needle and seat with a Q-Tip stuck onto a drill and some metal polish. Check out YouTube for some demonstrations.
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Wild Handyman
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Post by Wild Handyman »

dasscooter wrote:If it comes back, you can polish the needle and seat with a Q-Tip stuck onto a drill and some metal polish. Check out YouTube for some demonstrations.
Yes, of course it came back. Anyone know where I can buy a new KEIHIN carburetor? I don't want to waste another whole day of my life screwing around with this problem.
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az_slynch
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Post by az_slynch »

Beyond the needle and pin, is there any fuel in the float itself? I'm wondering if it's got a pinhole leak and isn't, well, floating right.

I think it's an 18mm, maybe from the VM series. For what an OE would cost, consider the Polini kit with the VM22 carb.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
djp4059
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Post by djp4059 »

I have the stock Keihin carb from my 2013 4T. I re-jetted it and have extra jets for it. If you want it you can have it, just send me a PM.
Tipper
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Post by Tipper »

This happened to me while riding and culminated in fuel pooling on the hot exhaust. The float pin had worked loose. I fixed it then carried on riding keeping an eye on the mirror to check that my scooter wasnt on fire.
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Wild Handyman
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Post by Wild Handyman »

az_slynch wrote:For what an OE would cost, consider the Polini kit with the VM22 carb.
After wasting yet another day of my life on this #$@&% scooter I ordered the Polini. I sincerely hope it will bolt right on and I can enjoy riding once again.
dasscooter
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Post by dasscooter »

It'll be much easier to polish the needle and seat than it will be to install aftermarket parts and make them work. You'll likely have to rejet it for it to work correctly with the stock engine.
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Wild Handyman
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Post by Wild Handyman »

dasscooter wrote:It'll be much easier to polish the needle and seat than it will be to install aftermarket parts and make them work. You'll likely have to rejet it for it to work correctly with the stock engine.
Oh, the original carb doesn't leak fuel anymore; cleaning the float pin and seat worked like a charm. Now, after disassembling and reassembling the stock carburetor a fourth time, I just can't get the scooter to run right. It starts, idles and revs great in the garage but stalls out after about a mile on the road... and I can tell you that at 64 years old pushing a scooter back home in the summer sun is a joy beyond measure. I may have messed something up, I don't know. My hope is that the Polini carb will run better than the stock carb. It certainly can't run any worse than the one on the scooter right now. And, if worse comes to worse, I can send the scooter to a competent mechanic with both carbs and a bucket full of money and beg for it to be fixed.
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jimmbomb
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Post by jimmbomb »

Maybe kinked fuel line, but you fixed that already.
Now im thinking that you need to drull out your gas cap or get a 2t gas cap.
Cheaper than a new Polini carb (which I struggled with then sold to azlynch)
Good luck
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Wild Handyman
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Post by Wild Handyman »

I guess I should have expected this with Scooterworks, having purchased items from them in the past, there are no instructions at all with the Polini carb, which is actually a Mikuni carb (?). None. Zero. Zip.
Thanks a lot, Scooterworks!

I have decided to take the scooter to a local motorcycle shop that has said they will work on Stellas and let a professional either fix the existing carb or replace it withe the Polini carb. I'm done wasting my life on this thing.
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jimmbomb
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Post by jimmbomb »

When i changed the stock carb on a 2010 stella to the Polini, it was a simple bolt on.
2 bolts, add spacer manifold. Bolt up.
Just the choke cable was weird, as I recal.
Good luck
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Yalzin
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Post by Yalzin »

Just a thought, as I recall having a similar "Drive it down the road for a mile or so, and it dies..."

...How full is your gas tank? There was a point where I would fill it perhaps a little too eagerly (or just more than 3/4 full), and gas would get into the Evap system, causing the bike to turn off. Very, very frustrating to troubleshoot.

I ended up disconnecting the Evap system, and getting a vented gas cap (from a 2T) instead.
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jimmbomb
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Post by jimmbomb »

Yalzin wrote:Just a thought, as I recall having a similar "Drive it down the road for a mile or so, and it dies..."

...How full is your gas tank? There was a point where I would fill it perhaps a little too eagerly (or just more than 3/4 full), and gas would get into the Evap system, causing the bike to turn off. Very, very frustrating to troubleshoot.

I ended up disconnecting the Evap system, and getting a vented gas cap (from a 2T) instead.
Agreed..
J H
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Post by ArgonV »

Mine would die after about a mile down the road when I first got it. Ended up pulling one hose from the gas tank top to the evap cylinder valve out, and using that as a vent hose. Has worked fine ever since.
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Wild Handyman
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Post by Wild Handyman »

jimmbomb wrote:When i changed the stock carb on a 2010 stella to the Polini, it was a simple bolt on.
2 bolts, add spacer manifold. Bolt up.
Just the choke cable was weird, as I recal.
Good luck
The choke on the carb is a different type (instructions would have been nice to hook it up with the supplied cable), but the intake manifold had an added nipple for some kind of vent hose that does not exist on my scooter. What do you do with that? To top off my frustration with Scooterworks, I sent them a message asking about the lack of instructions and the person, whose job it is to answer questions, is on vacation for a week.

To add insult to injury, I take the scooter to the shop that said they would work on it, I open the trailer and the mechanic (owner?) I was speaking with takes one look at the bike and says, "Not interested." Nice. Since a different mechanic agreed to take a look at the scooter they accepted the repair job. It's like God is trying to tell me I need to get rid of my Stella.
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Post by phunksoulbrotha »

I got my Polini carb from SIP in Germany and it didn't have any instructions either. I believe that fault is on Polini or whomever is packaging the units, not Scooterworks.

The included choke cable will work but you will have to decide which of the 2 little silver elbows or cable guides to use. The hardest part of installing the choke was that my cable guide had a little bump on the inside that the end of the cable kept catching on. I had to take a pair of snips to the cable end just a little to squeeze it through the tube without getting caught. Also, when taking the original choke cable out, the second clip in this link http://lmlocgb.co.uk/phpBB3/viewtopic.p ... 3&p=123964 should not come off completely or I don't think you'll get it back on. It just twists to the side but it took a bit of work to get it figured out.

The intake manifold should have a small little (tube) vent coming off of it. My carb kit had a small, rubber vacuum plug that you throw over that to cover it. I don't recall seeing anything similar when I removed my airbox and elbow that were attached to the OEM carb so that added some confusion for me as well. If there was something similar attached before I tore it all apart, it was part of the evap system that is completely gone now.

Do a bit of searching through the forum here and the LMLOCGB forum. I know next to nothing about engines and with some help from my buddy, I was able to get the whole thing installed relatively easily but I had to refer to the forum quite a bit for help. There are a few threads I had to keep referring to and they are a bit scattered, but I got it done. I agree with the others, the jetting is going to be the most frustrating. I had a shop mechanic jump in for that bit.

I recommend getting a new air mixture screw for the Polini carb as the supplied one is hard to reach once installed. I ordered this one http://www.minimobracing.com/store/p327 ... _info.html but shipping was almost as much as the screw.
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Post by Tipper »

The little tube on the manifold is there as part of the EU emissions crap (the SAS system) I am not sure if your American bikes have the same system but you can just block the tube.
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Wild Handyman
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Post by Wild Handyman »

Got my scooter back from the local motorcycle mechanic today and it turns out the problem was a clogged vent line. I guess I need to remove all the emissions crap so it continues to run.

Along with the bike I got my "Polini" carb back still in the box; the mechanic couldn't figure out how to install the darned thing, so I don't feel so bad. That piece of crap will be going back to the really helpful folks at Scooterworks.
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Post by jimmbomb »

ArgonV wrote:Mine would die after about a mile down the road when I first got it. Ended up pulling one hose from the gas tank top to the evap cylinder valve out, and using that as a vent hose. Has worked fineI ever since.

Can you tell us which hose you yanked? There is 2 of them, right?
Thanks
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Post by ArgonV »

The hose going from the top of the gas tank under the seat to the little black cylinder next to the seat lock. There are two hoses that go into that cylinder, just pull the end of the hose at the cylinder and it will then be used as a vent.
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