Fuel weeping

[mphayes]

Having problems when using or moving bike with fairly full tank of fuel on my 83 Hailwood
I have a circle of fuel around base and can hear it venting. Is it not venting properly.
Looking for feed back before I just start buying !

Thanks..........m

[BevHevSteve]

remove and clean your fuel cap, there is a small hole in it somewhere for this........ sounds like it's plugged up.

[mphayes]

Thanks Steve, wondered if it may be gasket issue.
I'll try low air pressure to clear.
Was thinking possible gasket issue.
Again thanks..........m

[mphayes]

It may vent threw key, not sure.
I don't have issue with Darmah gas cap, no key.
I think it's venting but some how fuel is coming with air.

Again I have a circle of fuel/moisture? present on top of tank??
Thanks for any replies...m

[mphayes]

best solution was to replace cap. Thanks Steve and others for suggestions.
Steve thanks for customer service and getting new cap out for me.
Hope I've enclosed picture so you can see my work in progress.
Have screen on and lower fairing is done just like the look without it.

[BevHevSteve]

looks good, glad to help.

[DvrMik]

Hi Steve, very similar problem (1983 MHR (S2 frame)). When I fill the tank (just below the prescribed limit) petrol pours all over the tank as soon as I shut the cap. It's like its syphoning out. If I open the cap, it stops. Close the cap, petrol starts pouring down the outside of the tank and onto my hot engine! Doesn't do it at lower fuel levels.
I have removed the cap and inspected the main seal. Seems okay and I can confirm it is sitting on the tank opening lip. I also took the cap apart and checked the thin rubber disk in the vent. Also seemed okay but i can't find any drawings, so can't be sure if the last owner meddled with it.
I realise a new cap may fix it, but what if it doesn't? I don't have spare money....
Any suggestions, spare seals, assembly diagrams etc would be very helpful.
If anyone is open to taking their cap apart and posting pictures that may also help.
Thanks, Mike

[DvrMik]

Hmmm. The plot thickens. I have now found a couple of images of the underside of the replacement caps. They look sufficiently different to mine to make me question whether the seal is indeed pressing down on the tank lip.
I think I'll be buying a new cap.....