How does the fuel tank vent on a nc23?
Or for fuel to come out air must be able to get in and mine seems sealed?

Reason I’m thinking mine has a issue is if I suck on the fuel tank (obviously empty) not a lot happens unless the cap is open.
Is this normal or does my cap have a blocked vent?
I brought the bike after it’s sat for 7 years so just going over everything

twostroker wrote: Mon Feb 26, 2018 6:50 pm How does the fuel tank vent on a nc23?
Or for fuel to come out air must be able to get in and mine seems sealed?

Reason I’m thinking mine has a issue is if I suck on the fuel tank (obviously empty) not a lot happens unless the cap is open.
Is this normal or does my cap have a blocked vent?
I brought the bike after it’s sat for 7 years so just going over everything

Does the BIKE START?

Yes but I have only seen it run for a few seconds
I didn’t fancy running a engine on oil that’s at least 7 years old.

The vent is only there to allow air in to replace the fuel used. So if the cap is shut and the fuel tap is shut and there is no change in fuel level then you will only be able to suck so much air before you reach a certain point that your lungs can't exceed.

I wouldn't worry as you have proved the vent isn't blocked because you are able to suck air through it with the cap open.

When you open the cap, there is a small hole to the left I think. This connects to the metal pipe running across the opening on the inside of the tank. It feeds down and out under the tank. I poured some thinners then petrol down there to clear mine out and rub some petrol into the cap seal to soften the rubber seal. I think that's the vent hole as I cleared that and didn't have further issues.