Fuel Tank over flowing.

[Kryten]

Ever since I put Skruffy Kat back on the road I have had a minor issue with the fuel tank overflowing when freshly filled.

Clearly the obvious answer is to do what I do and not fill it up to the filler neck of the tank, but if I am doing a longish distance such and when we went to Denmark for EK8. It would be nice to use the full capacity of the tank.
It would seem that I need to leave about 1/2 to 3/4 of a litre of ullage space to avoid the fuel expanding with the heat either from the engine or on a hot day to avoid it seeping out of the filler cap and running down the tank onto the hot engine!

Was considering lining the underside with a heat reflecting foil. Anybody done this or have a different solution?

[fossie]

Is it not more likely the rubber ring that seals the tank being damaged due to ethanol / old age .
You should be able to turn the tank over and it not spill.
Is the vent hole partially blocked ...open enough to allow air flow to energise the flow but not enough to vent vapour.

If it caused by heat surely you get pre ignition symptoms as the fuel would be too hot and everyone with you on that trip would suffer the same .

[Pedda]

Rubber seal most likely. No wonder after 4 decades.

[Kryten]

Rubber seal most likely. No wonder after 4 decades.

Could be. Although the fuel cap assembly was a new item when I got Skruffy Kat back on the road.

Did the replacement seals ever get made up?

[fossie]

A German had done made up not sure if there are any left though ...can't remember who Christian seems to ring right but .....a search through our history should reveal that info.

[Uncle Bob]

Ah, I'm not alone, the Swiss Katana does the same. I was going to ask where the vent hole is, as the tank has been lined previously and I wondered if it is blocked, but not sure where it is. If you find out who the German was who made the replacement rubber seal, I'd have one, but it doesn't really fix the issue, just tries to mask it.

Last summer (very hot day) I had just filled up and got a couple of miles when I stopped to let a load of teacher escorted school kids cross the road and while stopped I looked down to see rather a disturbing amount of fuel running down each side of the tank! Question was I to ride off through them to try and get the level down (not a good look with kids jumping left and right) so I had to chance it and sit there and risk spontaneously combusting with the subsequent mental scars on a whole year group of kids watching a Katana and rider looking like the DVD cover of Ghost Rider! Luckily they crossed fast and I was able to carry on before said combustion occurred!

[Kryten]

Ah, I'm not alone, the Swiss Katana does the same. I was going to ask where the vent hole is, as the tank has been lined previously and I wondered if it is blocked, but not sure where it is. If you find out who the German was who made the replacement rubber seal, I'd have one, but it doesn't really fix the issue, just tries to mask it.

Last summer (very hot day) I had just filled up and got a couple of miles when I stopped to let a load of teacher escorted school kids cross the road and while stopped I looked down to see rather a disturbing amount of fuel running down each side of the tank! Question was I to ride off through them to try and get the level down (not a good look with kids jumping left and right) so I had to chance it and sit there and risk spontaneously combusting with the subsequent mental scars on a whole year group of kids watching a Katana and rider looking like the DVD cover of Ghost Rider! Luckily they crossed fast and I was able to carry on before said combustion occurred!

Must have been a decent school, as a carelessly discarded roll-up ciggy would have been a disaster

My experience was not quite as traumatic, but I did get told off by El Presidente for needlessly polishing the tank at a rest stop in Germany while on the way to EK8

[fetishkat]

I have the same issue, only in very hot weather. As long as I only fuel up to just below the inside of the filler body and get going straight away then no worries, if I fill up then go for a brew then I’m asking for trouble with fuel bubbling up everywhere.