Tank suck: Beware!:

[Zoom Zoom]

After a year of having the LeMans and never having any trouble, I experienced the tank suck issue. I have yet to remove the tank, nor has the bike ever been down or set on its side for maint. The valve simply decided to stick out of the clear blue.

 

Now, when I discovered it, I figured I would keep an eye on it and vent the tank when needed. Within 1 mile of the gas station, the bike began running poorly and I returned home to swap for the EV. Within 3 miles the tank had built up enough vacuum to leave a dent in the tank! The dent is at the bottom edge if the area where your knees go. It's not real bad but I notice it. It also cracked the paint there. Thank goodness it is still under warranty. Thanks to T Whittaker for the quick fix. I'll be removing that valve soon.

 

Zoom Zoom,

John Henry

[jrt]

John, removing the valve is one fix, the other is to address the root cause- the tipover valve isn't operating properly. Almost always, it's just that the valve is not positioned vertically (exactly vertically) although if yours was working for awhile, then not working...it could possibly be the valve (or it moved?).

 

BTW- I just removed the grommet under the filler cap. That's another quick fix. Downside of that is if you drop your bike, gas can leak out.

[dlaing]

Downside of that is if you drop your bike, gas can leak out.

And the bike can go up in a ball of flames.

It happened to atleast one forum member's bike.

Luckily he was not also incinerated.

 

FWIW I sliced a small V-section out of my tank's grommet.

Using this method, the fuel will leak out more slowly than no grommet, but it only takes a little fuel to make a big fire

 

Also please note, Guzzis by the nature of the spark plug placement in the crash zone, are probably more prone to crash and burn syndrome than many other bikes.

 

So, the moral of the story is to get them to fix the tip-over valve

...and get a good pair of head guards.

[jrt]

Or crash guards.

 

But honestly, I've been riding Guzzi's for over 20 years, and hardly ever hear of them catching fire (cue up freddy krueger picture!)

[Zoom Zoom]

Yes the gromet is the temporary fix. I have no intention of leaving it that way. As to the valve, I can't believe it moved all by itself changing its orientation with vertical, but it may have happened. I will probably replace the vent line back to the bottom of the bike and leave that valve out. That totally resolved the issues with this on the EV. Whay really puzzles me the most is that nothing changed that should/could have caused this.

 

Oh well, I mainly wanted to give you all a heads up that, without warning, the valve can stick, and it can permanently damage the tank.

 

Zoom Zoom,

John Henry

[ferguzzi]

Good to know. Yet another landmine to avoid. Dear God will it ever stop....

[Tom in Virginia]

Recently (last weekend) had this occur on my '03 as well. Issue cropped up outta no where.   Manually vented it for the ride, waiting for it to get back above 50 before I go pull the tank and investigate.  Haven't noted any damage to tank yet, but man, that tank can hold A LOT of vacuum, almost scary when I open the fuel hatch.

[bikelee]

New to my Rossa Corsa. I opened the gas cap a heard a slight rush of air. The bike just been sitting in the garage. Can someone tell me where the tip-over valve is and what it looks like ? Will I have to take the tank off to fix it ? Thanks, Leon.

[SCole]

Leon,

 

I am new to Guzzi's also and found mine last night horizontal to the side of the right fuel injector. I did not have to remove the tank to see it.   And of course I have the same tank suck problem you are having.  So it needs to be verticle and the only way that will happen is removing the tank to strap it to the frame with a longer hose I am guessing?  Soemone who has done this can weigh in I bet.  Thanks!

[dangerous]

hang on... whats all this tip over no suck talk all about?

I cant see any thing on my 04 V11 and if its on the right injector hows that help or cause the tank to not allow air in? 

surley if a tank presurises so bad it sucks its self in the injectors wone get any fuel?

[GuzziMoto]

The tip over valve is an emissions piece. Your bike probably does not have one.

The injector is simple WHERE the valve was sitting, it is connected to the vent hose for the gas tank and closes the gas tank vent in the event of a tip over.

[dangerous]

na my gas tank vent is just a nipple under the tank, it goes no were, so yeah all makes sence that I dont have one and it must be a US emisions thing

[GuzziMoto]

"my gas tank vent is just a nipple under the tank"

I would highly recommend you add a length  of hose to that nipple if there is not already and route it down to somewhere at the bottom of the bike, like between the swingarm and trans.

That way if the tank gets over filled or what ever and fuel comes out of the vent it is not draining directly on to a hot motor. That would be bad. Just make sure the hose is not pinched or blocked. At least some of them have two nipples, one for the vent and one for the filler neck drain. Both these can be T'd together and run down to the bottom area of the bike as one line.

[dangerous]

At least some of them have two nipples, one for the vent and one for the filler neck drain.

as does mine, all this being new info for me thanks to a recent thread I started about the over flow being blocked. I have a hose on the over flow  but not the breather (was the other way round) I will sort one out for each... soon

 

So the valve that this thread refers to is on the fuel line right? cos that would be the only way you would stop gas spilling in a tip over?

The way ya all talk its in the vent line which if blocked of only stops air getting into the tank to help petrol to depart?

[GuzziMoto]

 

"So the valve that this thread refers to is on the fuel line right? cos that would be the only way you would stop gas spilling in a tip over?

The way ya all talk its in the vent line which if blocked of only stops air getting into the tank to help petrol to depart?"

The valve SHOULD be on the vent line. I say SHOULD because Guzzi's, being hand built as much as they are are sometimes not assembled as intended.

The purpose on the tip over valve is to allow the fuel tank to vent, that is to allow air to enter the tank as fuel is being used out of the tank, yet in the case of a "tip over" the fuel in the tank cannot spill out of the tank through the vent. The other line runs to the area around the filler hole. That area is closed of from the tank when the cap is closed so there is no way fuel could spill out of it unless the cap was not closed. It allows excess fuel that may have been spilled there or water (i.e. rain) that may accumulate there to drain off so that when you open the tank there is nothing there to enter the tank.

I hope that helps.

Boy I F'd up this post.