Fuel Tank Vacuum

[Tom Herold]

Being a new Tiger owner, I'm perplexed by the huge amount of vacuum generated in the fuel tank.  Every time I've gone to refill, it's an effort to pry the filler lid open. Once it does start to open, I can see the tank flex as air is sucked in.  For a fuel injected engine, this doesn't seem right to me.

My Sprint ST's running a plastic tank and a 955i engine, and I don't have this issue,

Anyone else experiencing anything like this?

Thoughts?

[bahtiger]

Sounds like your vent line is pinched.

[John Stenhouse]

Clear your vent line, also check the connections on the left rear of the tank, two steel nipples the vent lines connect to. On my Tig they get clogged up solid and need taking out and reaming through with a small file

[Mustang]

Clear your vent line, also check the connections on the left rear of the tank, two steel nipples the vent lines connect to. On my Tig they get clogged up solid and need taking out and reaming through with a small file

Yep the nipples screwed into the tank will corrode inside and sometimes you need to run a small drill thru the nipples to clean them out they get so corroded
on the steamers there is also a drain line to let water that gets under the cap drain off so it won't get into the tank , that one plugs up too and needs cleaning once in a while .
Don't know if the girlies are the same

[Tom Herold]

Vent lines! Got it, I'll tackle them after work tonight!  Sometimes the simplest things escape the mind...... Thanks for the assist.

[John Stenhouse]

Girly is exactly the same Mustang, I know when mine need doing you open the tank and there's water sitting there.  :shock: