Modern Buddy

It looks like my 4T has the Stalling problem I've heard mentioned here.

It does it at full throttle, it does it at low throttle, sometimes it just conks out at lights.

So far I've tried the following: Replaced the gas cap with a old 2T Cap, my 2T cap is pretty crappy and corroded so I'm not sure how well that's working.

Unplugged the hoses from the anti-rollover valve, Plugged the one from the tank and left the one from the bike open.

Moved my fuel line around a bit, I think I may shorten it as it goes down and then up again before it gets to the carburetor.

I don't have a warranty since I'm not the original owner.

Sounds like what mine was doing. Ended up needing the stator replaced.

Does it start right back up or take a while? Each day it took longer and longer to start until it didn't start anymore.

Starts right up again usually.

Doesn't feel like a loss of spark, Feels like it's loosing fuel and going lean.

Probably evap system issue. Not sure swapping to a 2T cap will help much, as it didn't have this system in it. Drilling 1/16" holes in the 4T cap works well.

Has the problem persisted since you plugged the hose?

You may still have some gas in the air system or possibly flooded the filter.

Ooh, Thanks Eric!

I have not checked the air filter yet. I hear it's a pain to get too, Gotta drop the shock bolt and everything right?

Problems have persisted, I wasn't sure if I should plug the hose going back into the body of the bike from the anti-rollover valve or leave it open to atmosphere.

ericalm wrote:Probably evap system issue. Not sure swapping to a 2T cap will help much, as it didn't have this system in it. Drilling 1/16" holes in the 4T cap works well.
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Using a NEW 2T cap helps. That way you are sure the vents are not plugged. I got mine from Scooterwest.
I drilled the 4T cap in several places, but it did not help as it has a membrane in it which basically self seals the holes.

desmolicious wrote:

ericalm wrote:Probably evap system issue. Not sure swapping to a 2T cap will help much, as it didn't have this system in it. Drilling 1/16" holes in the 4T cap works well.
.

Using a NEW 2T cap helps. That way you are sure the vents are not plugged. I got mine from Scooterwest.
I drilled the 4T cap in several places, but it did not help as it has a membrane in it which basically self seals the holes.

You must pierce the membrane! I did two in the top, then one on each side; works fine!

ericalm wrote:

desmolicious wrote:

ericalm wrote:Probably evap system issue. Not sure swapping to a 2T cap will help much, as it didn't have this system in it. Drilling 1/16" holes in the 4T cap works well.
.

Using a NEW 2T cap helps. That way you are sure the vents are not plugged. I got mine from Scooterwest.
I drilled the 4T cap in several places, but it did not help as it has a membrane in it which basically self seals the holes.

You must pierce the membrane! I did two in the top, then one on each side; works fine!

Greasy pierced mine in three separate places. I witnessed the drill going all the way through. Did not work. He even did the simple test of trying to blow air through it. Nothing doing.
Maybe some membranes are thicker than others? Maybe some are missing them?
Anyway, getting a NEW 2T vented cap worked. I emphasize new to make sure it is not plugged up with gunk/dirt etc.

It's also possible that if I hypothetically bypassed the evap system (which would be illegal) the cap didn't need any more venting than it has. Either way, no hypothetical evap issues for me since I did this on 4T #1 and never had any since I hypothetically did this on 4T #2 the day I got it. This is all based on computer modeling, though.