Modern Vespa

All,

Is the gas cap vented on the LX150? I am guessing not, as I read the fuel tank has a breather hose.

Is my understanding on the gas cap and breather hose correct?

Ehaughn,

While not definitive, I just bought a 2006 LX150 and I was also interested in potentially replacing the old gas cap as I thought it might, due to age, not vent effectively. I took the rubber seal out and inspected with a light and magnifier but could find no vent hole.

Assuming my gas campus original, as it looks to be by the manual's pictures, I don't believe it's vented.

there is a breather hose. You can test it by overfilling your tank...

Does the breather hose connect to the vent on the carburetor? The left side of the carb?

Sort of, it's complicated.

Goes to a rollover valve then to a T fitting with hoses going to the left side of carb and EVAP canister then from canister to fitting on intake tube to pull vapors out of canister and carb. Why many owners do an EVAP delete. See page 47.

https://www.af1racing.com/ProdImages/st3/EVP4000US2.pdf

Thank you, the document was most helpful.

A few comments.

The gas cap is not vented.

The jets/carburetor is the same for both the electric fuel pump and vacuum petcock.