83 GS750ESD. Gas cap woes

[Anonymous]

I am slowly learning as I go. Thanks for all the help so far. Today's problem. After sitting in the parking lot in the rain all day, the bike required full choke to start. When I slowly d-choked it, it wuld stall. On a hunch, I put the key in the gas cap and unlocked it. There was a "woosh" sound and a squirt of moisture shot out the keyhole! Is there a vent that might be plugged up? Why would something squirt out, is the tank pressurised?
After re locking the gas cap, the bike fired right up.

[moto_dan]

No the fuel tank shoud not be pressurized. You probably have a plugged or pinched vent. I believe the vent hose comes off the fuel gauge sending unit.

[Don Lobacz]

On the older bikes, I'm pretty sure that the gas cap itself is the vent. The drain tube coming from the fuel level sending unit is there so that if there is a leak there it does not drip directly onto the hot motor.

[moto_dan]

On the older bikes, I'm pretty sure that the gas cap itself is the vent. The drain tube coming from the fuel level sending unit is there so that if there is a leak there it does not drip directly onto the hot motor.

You're probably right Don, thanks for the clarification.

[Anonymous]

On my 83 GS750E, sometimes when the sun has been beating down on the bike in a parking lot or something, if I lean the bike a certain way, I get the same whooshing sound from the cap area... Prolly just built up pressure, so i would agree with the above... Check your vent (wherever it may be )

[Anonymous]

Vapor pressure can build up in the gas tank through warming by engine heat or weather. Excess pressure should vent through the gas cap after pressure has built up to a threshhold level. I agree with other posts that it sounds like your gas cap is faulty. My bike vents through the gas cap for about 15 to 20 minutes after a "hot" ride. Venting often doesn't start immediately upon parking but rather after the engine heat has had 5 minutes to warm the tank. Besides releasing excess pressure, I believe that the gas cap should also admit air as fuel is consumed by the engine. If it doesn't do this, symptoms of fuel starvation will appear.

Simon