While rebuilding my nc30 carbs I cant seem to get flow through one of the tubes.
Does anyone know what this is for and where the other 'end' is?

Im not a 100% sure but id imagine it's either an over flow and/or float bowl breather, but what's with all the instant gasket?

that pic is from cammos carb thread originally buddy!

I didn't know that, as you can see im new to the site, but im still shocked any one would use instant gasket for that job! as you can see from the pic the instant gasket seeps out both sides of the joint, only takes a very small amount to find its way into the float chamber and into a jet to really spoil a ride out or good day at the track.

That is the Starter jet.

Try opening the choke and seeing if you can blow through it.

I concur, silicone sealer is bad, but sometimes essential if doing a quick repair.

Racer-X wrote:but im still shocked any one would use instant gasket for that job! as you can see from the pic the instant gasket seeps out both sides of the joint, only takes a very small amount to find its way into the float chamber and into a jet to really spoil a ride out or good day at the track.

LOL those are my carbs!

They get taken apart for a full inspection and clean after every track/race day. I used instant gasket because 50 quid (yes you read that right...) is too much to pay for genuine gaskets. Touch wood but I never had a carb problem because of the gasket goo.

Since that pic was taken a couple of years ago I've been using Rick O's substitute gaskets which work a treat and are cheap.

@Timon: yes you should be able to get air or liquid through that orifice, the other end comes out near the standard velocity stack (there are 2 brass outlets there - it's the smaller one, the other is the air jet). Open the choke and try some good carb cleaner, compressed air or fuse wire etc to clear it out.

Cheers guys, very helpful.

Sorry for robbing your picture Cam, as you can prob guess you carb guide has been most useful to me