Has anyone ever taken a gas cap apart?

[DruBaby]

When I got the new tank for my '94 last year (from e-bay), the key the place sent me didn't open it. Grrrrrr.... I took it to my local locksmith who took the cap apart and re-keyed it to match my ignition. It was great - sort of. I think he replaced a part 180 degrees out because now my tank doesn't vent. It will build up pressure, especially when parked in the sun. The pressure causes the fuel to flood out the carbs. What a pain! I need to take the cap back and have him fix it, but I'm not sure what part to tell him to change. Does anyone have experience with this or know of a source I can look into? Thanks!

[The CyberPoet]

If it he put it on backwards, open the gas cap with the key, unbolt the allen bolts around the outter ring, lift the entire assembly off and reverse it, then bolt it back down. Three minute job.

When installed correctly, the cap will pop open with the hinge on the side towards the rider.

Cheers
=-= The CyberPoet

[toobalicious]

remember that four of the bolts are dummies ...
a

[DruBaby]

You misunderstood

It does open with the hinge toward the rider. The problem isn't how the cap is mounted on the tank - I did that part myself - rather something internal within the cap itself. Have you ever taken one completely apart?

[Black_peter]

The vent is not effected by the cap..
The vent is under the mounting ring, between the screws at 10 o clock and 9 (I think) ..
It is just a hole (looks like a screw hole)
I just had this same thing happen last week end.
(I was away on business and wasn't able to post about it) My guess is that the vent is blocked.
I blocked the vent while painting and forgot to unblock it.

Mine does this: The vent tube( out to air)
exits to the left (looking from the top) of center and mid way front to back. The vent tube (to the tank) is a 90 degree tube about 2 inches in front of that.
I have both open for now, there were no lines on it when I got it. I need to connect these tubes with vacuum line other wise when I tip the tank gas drips out of the vent. I'm not sure if you have this.
I'm thinking my tank does because this is where the charcoal canister would tie in but it is worth looking to see if the tube got crimped.
If you don't have this external tubing remove the gas cap, find the vent hole and press a rubber tube up to it and blow.. you should be able to blow air through the vent hole and maybe even hear the air inside the tank. just air not bubbles. A thin long wire can also be pushed in there to see if it may be blocked by a bug or something.

I had gas spray about 12 feet when I disconnected the fuel line from the
feul cock.. texas heat+no vent.. I'm lucky I didn't blow the thing up..

[DruBaby]

Peter,

I tried removing the cap and had no trouble blowing through the hole. I was under the assumption that this hole is an overflow in case you overfill your tank while not paying attention at the pump. If there is a tube that runs between this hole and the outside of the tank underneath, how would that affect the venting of the tank? When the gas cap is closed, there's a rubber gasket that seals the cap to the tank to prevent fuel spill and therefore, fuel doesn't get to the hole you mentioned (that I can figure our anyway . Help! I'm confused here.

[The CyberPoet]

Peter,

I tried removing the cap and had no trouble blowing through the hole. I was under the assumption that this hole is an overflow in case you overfill your tank while not paying attention at the pump. If there is a tube that runs between this hole and the outside of the tank underneath, how would that affect the venting of the tank? When the gas cap is closed, there's a rubber gasket that seals the cap to the tank to prevent fuel spill and therefore, fuel doesn't get to the hole you mentioned (that I can figure our anyway . Help! I'm confused here.

The hole and hose assembly serve multiple functions. When parked, it acts as a drain for rain water that might get into the cap area. When the bike is running, it acts as a vent to permit air to replace the fuel as the fuel level drops. If either the vent line or the rubber seal at the cap aren't working right, you may not get the venting (vacuum suction at the gas cap when opening it -- big swooshing sound) or you may get rain water into your tank (rust and possible stalling to follow).

Cheers
=-= The CyberPoet

[DruBaby]

No, I don't get the "swishing" vacuum sound when I open the tank. Quite the opposite. The tank is pressurizing and I get a blast of fumes and air coming OUT. The gasket is obviously working ok. I really hate to take it back to the locksmith to re-assemble if I don't know exactly what the problem is.

[The CyberPoet]

No, I don't get the "swishing" vacuum sound when I open the tank. Quite the opposite. The tank is pressurizing and I get a blast of fumes and air coming OUT. The gasket is obviously working ok. I really hate to take it back to the locksmith to re-assemble if I don't know exactly what the problem is.

Same basic concept, except that in your case you're talking about being parked in the heat (heat-related expansion) rather than suction from fuel consumption. Check the venting.

Q: Are you riding a California model? I ask because they have special plumbing, in which case the problem probably lies in a fault PCV valve to the charcoal cannister.

Cheers
=-= The CyberPoet

[Black_peter]

DruBaby Sorry I confused you.
the hole by the filler runs down and out of the tank.
it does not connect to the "inside" of the tank.

the true tank vent is under the tank. With the fairing off you should be able to see it. Left hand side of the bike, almost in the middle (closer to the seat if anything)
There is a stub about 3/4 inch long coming out of the tank if you have a hose on there make sure it isn't crimped or plugged, if there is no hose, attach one and see if you can blow through it.
I belive this pipe is straight and you can clean it with a wire of some kind.