Fuel vapours

[lil4399]

I seem to be getting quite a few occasions of "petrol fumes" wafting up when I stop at junctions, I have checked for leaks but I am sure it is coming from the fuel cap.

When I had the filter out the fuel leaked (slightly) from the cap, also, washing the bike just now I threw warm water over it to rinse it (dry faster) and the cap hissed!

The question is, can you change the seal?

[KiwiCol]

If it hissed, (because of the hot water rinse) I'd be inclined to check the tank breather is clear & not blocked / bent.  Any expansion should go out the breather (being the path of least resistance) I'd of thought.
Sounds like you're pressurising the tank while riding (fuel slopping round giving off more gas) and when rinsing with hot water, with a blocked vent hose, it has nowhere to go except push out through the cap.

Alternatively, new caps and aftermarket ones are avail, think Notty brought an Oberon one not long ago, he might still have his original?

[lil4399]

So I might of kinked the breather pipe reinstalling the tank. Sounds plausible Kiwi, I have a long ride tomorrow so should have a low level of fuel when I get home so will take the tank off to check.

I know it's not blocked as it leaked fuel when I had the tank off a couple of wreaks ago.

[Notty]

If it hissed, (because of the hot water rinse) I'd be inclined to check the tank breather is clear & not blocked / bent.  Any expansion should go out the breather (being the path of least resistance) I'd of thought.
Sounds like you're pressurising the tank while riding (fuel slopping round giving off more gas) and when rinsing with hot water, with a blocked vent hose, it has nowhere to go except push out through the cap.

Alternatively, new caps and aftermarket ones are avail, think Notty brought an Oberon one not long ago, he might still have his original?

Yep still got it - happy to post if it helps 

[lil4399]

If it hissed, (because of the hot water rinse) I'd be inclined to check the tank breather is clear & not blocked / bent.  Any expansion should go out the breather (being the path of least resistance) I'd of thought.
Sounds like you're pressurising the tank while riding (fuel slopping round giving off more gas) and when rinsing with hot water, with a blocked vent hose, it has nowhere to go except push out through the cap.

Alternatively, new caps and aftermarket ones are avail, think Notty brought an Oberon one not long ago, he might still have his original?

Yep still got it - happy to post if it helps 

Cheers Notty, give me a day or two to check it out, weather shitty here at the moment and garage unavailable.

[froudy]

The strong fuel smell is probably to do with hot weather and the tank venting.
Mine does it if parked up with a full tank and in direct sunlight. You can actually see the fumes venting from the tank vent pipe.

The big rubber seal on the tank cap is not available as a spare part either which is a pain. Mine was picked up as an advisory at the last MOT as being slightly perished. Seems bloody crazy to have to replace the whole tank filler cap assembly just for the want of a seal

[grog]

mine sits in warm days, sometimes over 40, usual summer is 30 to 35. no idea why but never a smell or fumes.