What is the best way of dealing with it?

1. Vent to atmosphere
2. Vent to top of filler neck

i have the main pipe to the top of the filler pipe, and also a very thin tube from there out to the atmostphere 9in the wheel arch) so the tank can breath to replace fuel used, and also expansion/contraction of fuel due to temprature

my tiger breather pipe exits at the fuel filler bit. not sure whats right but you might have problems during SVA or FIA inspections with it breathing to wheel arch eg fire?? Oli.

You are fine either way as long as it has the relevant breather on the end of the pipe, I believe.

The Tiger cap has the breather in the fuel cap, but if you go to an aero style cap then you have to fit a bike style breather.

Mark.

As my fuel fillers are about 400mm from the tanks, I imagine that the breather from the tank to filler neck would avoid any airlock problems when filling with fuel. However this won't stop the tanks imploding when the fuel gets sucked out by the pump :eek:

Should I put a tee piece in so that it vents to atmosphere too? I'm a bit concerned that it might slosh out of the vent pipe under hard acelleration (vent hole is at the back of the tank)

Is there such a thing as a tank breather valve which lets gas in or out but not fuel?

yup, think auto do some things called breather valves for header tanks, fuel tanks, swirl pots etc.
not sure which is best tho.

http://www.thinkauto.com/

Russ.

I've put a tee piece in the fuel return pipe, vented to atmosphere. Was going to fit 1 way valve, but thought i'd have problems filling tank, ie air can't get in, so I didnt.
Works fine.

Marcus