Fuel tank breather?

Benyon · Apr 22, 2009

I have a braided pipe running across the roof of my engine bay ('72) which isn't attached to anything. Following it back it goes through a T junction then splits across each side, up into the air vents then back down & appears to go to the fuel tank. There is a distinct fuel smell and taste from the pipe which was suggested as a fuel tank breather by Hilly_70 yesterday. Would this have originally been attached to the air cleaner? or should it vent somewhere else? Should I just block it off or will this affect the fuel flow? advice appreciated...

Sorry for the poor photo...

halfpint_fighter · Apr 22, 2009

Yes it would have gone to the air filter, i disconnected mine when i put on twin carbs!

Benyon · Apr 22, 2009

Cheers Olly.

Is yours blanked off or just hanging loose like mine?

Araon · Apr 22, 2009

Yep the tank will have two vent pipes leading into the rear vents where you have two bulbs that allow the fuel vapour to condense back to droplets then they are combined with a tee and fed to the air filter, best bet is to reinstate it and on twin carbs one to each carb...

Haveacamper · Apr 22, 2009

the fuel smell may be coming from the elbow that comes out of the centre of the fuel tank - which is positioned behind the firewall so check this one out. this is the one that caused my fuel smell

NaFe

p.s. there is potentially a problem if you blank the end off. as the fuel is pumped from the fuel tank, if the fuel filler cap and all connections are very good then a vacuum can form in the fuel tank.

best bet is to tap it into the carbs, but at the end of the day if its in the engine bay it will get sucked in when running

Trikky2 · Apr 22, 2009

Tap it into the air cleaner otherwise you will still have a petrol smell when you turn on the heater.

halfpint_fighter · Apr 22, 2009

Mine has just had the pipe removed and no blanking plug. Hasn't caused any problems so far but i suppose at some point i will fit a hose to one of the air filters!