I tried to unblock the vent pipe with some wire , but it stopped short, just before it opens into the void at the filler cap. Try as I might I could not get the wire to unblock the vent hole, and compressed air did not work either.
Turning the tank upside down, I removed the fuel sender unit, and there I could see the vent pipe where it enters the "void"
I used a dremel to drill a hole into the vent pipe.
I then used some spring wire, with a sharp edge, attached it to a drill, shoved it into the hole, and started spinning the drill, and after a few secs, voila, the hole into the void was unblocked.
Using some "Pratley Steel" I sealed the hole, whilst gently blowing air thru the vent pipe with my mouth, so as to prevent the sealant from sagging into the hole. The sealant took about 10mins to cure, and the jobs done.
The cause was rust, and rust-proofing. When I got the bike the tank waqs badly rusted. The clowns that de-rusted the tank, and then sealed the tank, must have got the "sealant" into the "void" thus blocking the vent hole.
Gerrit
