Petrol tank

[Firery Fred]

There's  a small (5mm) vent pipe under this tank that I would like to blank off.1) I need to do this as we have moved the cap position and the angle it sits at , and 2)Will it be ok as long as I use a vented cap , cheers , Fred

[Firery Fred]

Oh , nearly forgot...how do I tell if the cap I have is vented?

[Olds]

Should be fine blocked off with a vented cap but it is possible to get a little fuel loss on uneven roads, so be careful on how far you fill the tank.
One problem you may have is fuel starvation if the venting is not adequate and you are running a very thirst motor.
Traditional cam lock caps will have a small hole underneath near the centre and another just outside the rubber sealing gasket.
My Harley vented twist cap has a valve built into the centre that allows air in freely but not out. Hence the use of the vent/overfill pipe.
The non vented cap is plain.

[Firery Fred]

THANKS PEEPS...monkeys to the rescue again