Modern Vespa

Where should the fuel vent hose go after the evap cannister removal is complete?

The vent hose comes out of the gas filler neck on the front and it turns 90 degrees to the right. I ran it between the right side of the frame downtube and the gas tank (about in the middle of the tank). Then, I cut off the excess. I did this about five months ago and it works fine.

Straight down to the ground. You may need to extend it.

Yes.........when I came down between the frame & the gas tank on the right side, I pointed the vent/overflow line towards the ground. I first tried to bring it out of the lowest-front part of the fairing where the scoop and painted plastic join but the wind kept pushing it up so I moved it. Now, there's no problem. The original line ran all the way to under the seat so there's a lot of excess line to cut off. By putting it where I placed it, it's secure, vents well and any overflow goes directly to the ground. I've only overfilled once doing this since the BV has a better tank design than the GTS/GTV models.

Question for jimc about the overflow tube.

When I removed the evap system, I cut the tube off just below the hole in the under seat compartment where it entered the rollover valve. I did not cut it short to hang to the ground. I suspect that, in an overflow situation, some fuel might remain in the tube where it begins to ascend upward. I have noticed some fuel smell on long and bouncy trips, but the performance does not seem to be affected at all. Does it matter? What, in your opinion, will be the consequences of leaving it this way, if any?

Thanks, Durdle

Your way is definitely the best way to do it. I just disconnected mine at the roll-over valve and gas can still travel up into the line a get "stuck" causing the same effect as having it connected. It goes away very quickly but will still vapor lock. Guess how I found this out . Over the winter when I take things apart to adjust the valves I will follow what you did and get it short and straight to the ground.

Bob

see above! 8)

Which bit of "STRAIGHT DOWN" did I miss out?

Jimc


Thanks for the non-answer. I ask a specific question on what you thought would be the consequences of doing what I did. Guess you have no opinion. That's OK too.

Durdle

No, really - the overflow tube must go down, down, down, with no 'up' in it. Or am I completely missing what you are asking?

I am simply speculating that if the hose goes down, then horizontal, then up slightly, the only thing that can happen is that a small amount of fuel could stay in the hose at the lowest point. I assume it would evaporate and cause no harm. I just asked for an opinion about that. Is there any harm in that?
I have no performance problems, but sometimes smell gas, which you probably do with the hose going down, especially if it is filled to full.

In asking? No. In the trapped fuel? Possibly - it doesn't actually vent the tank, you've deliberately left a 'trap' much as you might have under your kitchen sink.

I wouldn't - I'd re-route as per the rest of the world. Of course you'll smell gas when filling, let alone over-filling.

Your tank needs a vent, give it one.

Yes...............It will allow over-flowed fuel to stay in the line and prevent the tank from venting. This can cause the same symptoms as having a clogged canister.

As Jim said................Point it DOWN.

Anyone have pictures of where the end of the tube goes, and how to secure it to the bike? Thanks.

No pictures (sold my BV500) but the overflow tube comes off of the front of the scooter behind the plastic cover just behind the front wheel. The nipple points towards the right side so I just ran mine towards the right floor board and tied it with a nylon zip tie between the floor board and the frame. (pointed towards the ground)

I secured mine with a zip tie to a little hole I felt near the passenger footrest.