Locking petrol cap seals too good.

[Richard the old one]

I thought that it was only in the cold weather that I had a problem and I was assuming that ice was forming within the petrol cap and that this was not letting air in to replace the used petrol. However today when I stopped to top up my petrol after covering about 100 miles as I took the petrol cap off I could hear the air rush in.

Have any other owners found this to be a problem?

I have resorted to cutting a slot in the rubber seal to allow air into and out of the tank.

[GrahamFountain]

Once was sold a US spec unvented cap for the TR7. The fuel pump sucked the tank almost flat. Fortunately I got it from the local main dealer, who was still selling Triumph spares at the time. So they had to replace the tank and straps, etc. And the cap.

[2dollys]

The petrol tank has a vent hose,in the filler neck,check that its not blocked.PJB

[Richard the old one]

The vent hose goes from the tank to a point on the filler pipe which is below the filler cap it allows the tank to be filled but once the filler cap is in place there is no way that air can enter as petrol is used.

[2dollys]

Sorry Richard,I thought this was a vent.Cap problem then so.PJB.

[trackerjack]

Built a 4x4 Sierra based special in the late 90's and used it for grass trackstuff and it went like hell for a lap and then gradually ground to a halt after the event I tried the starter only to find it fired up instantly.....................a non standard tank and a cap with no vent!!!!