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Display Mesage #94298

Gas leak in vacuum line
Written by literidr on 6/20/2010 at 11:09 pm

Hey Leland,

Two of those hoses vent the chamber above the float bowls, the other hose goes
to a T that connects to the carburetor side of the slide diaphrams on both
carburetor. My guess is that the third line has a small amount of vacuum that
allows the engine to consume any vapor from the float bowls while the engine is
running. The large open hole is merely a vent to atmosphere to vapors
genereated once the engine is shut down. If you have fuel coming from the open
tube then you have a problem with one of the floats in one of the carburetors.
I would guess that one of the floats has developed a leak and is no longer
shutting the fuel supply off once the proper fuel level is achieved. That's
where I would start looking.

To check the float bowls, just remove the air cleaner, then loosen the clamps
that hold the carbs to the intake rubbers. Rock the carbs back and forth until
they come out of their rubber tubes, then turn the carbs over (fuel is going to
spill out) and remove the bowls to check the floats. Check the floats for fuel
inside them, and check the needles and seats to be sure they are securely seated
and the needles moving freely. Hopefully, this will help you locate your

John Handford, literidr@...
Taylors, SC
'90 PC "Spirit"
'94 PC "Chance"

--- In, "Leland C. Sheppard" <lcshepp@...> wrote:
> Hi Coasters,
> Douglas Van Bossuyt and myself have been trying to help Jim Day solve a
> mystery with his '96 PC. Jim lives in Hawaii and the local dealer won't
> work on the bike because it is over 10 years old...
> He has a small gas leak and the associated smell. I thought it would be
> the petcock but Jim tightened the screws (which were a little loose) and
> the smell persisted.
> I pulled some plastic off my '96 so we could compare notes and, with
> Douglas' help, we have determined the following:
> There is a little 4-way connector below and to the rear of the petcock.
> 2 of the lines coming from it are vacuum lines and 1 of those goes to
> each carburetor. We aren't sure where the 3rd line goes. The fourth
> connector is open on 49-state bikes. On CA bikes, an emissions hose is
> attached to this fourth connector. It is the 'Evaporative Emission
> Carburetor Air Vent Control".
> If Jim puts his finger over the opening from that connector, his engine
> speeds up. On mine the engine speed changes when I cover it. In both
> cases, I suspect the level of vacuum in the motor is being affected by
> closing off this connector.
> Jim is getting a small amount of gas out of this connector; none comes
> out on mine. What we are trying to figure out is where the gas is
> coming from. It's most likely from the carbs but how and why are not
> clear to us.
> Has anyone else experienced this and what did you do to cure it?
> Thanks for any info on this.
> Leland
> --
> Leland Sheppard
> Placerville, California, USA
> ...Life is good on the Pacific Coast...
> '94 Pacific Coast, "Black Beauty", 211,500 miles
> '89 Pacific Coast, "Shadow Dancer", 118,475 miles
> '90 Pacific Coast, "Red Baron", 106,100 miles
> '96 Pacific Coast/SuperSport sidecar, "Handsome Hannigan", 31,150 miles
> '02 Ural Patrol, "Boris Blueanov", 15,250 kilometers
> '89 GB500, "Little Bugger", 13,692 miles
> '02 GL1800, "Copper", 55,850, '07 Aspen Classic, "Copper's Camper", 1,545
> iPCRC #72; IBA #10582; AMA #481368
> Mother of all PC800 Web Site Lists:

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