Should I Be Able To Blow Down The Fuel Return

[Obey_R 23]

So I'm trying to work out my the regulator popped on my new carb setup.

 

If I take the return feed of the regulator and give a good blow, I can feel the pressure building then when I stop you can hear it hissing back out, whereas if I take the fuel cap off and blow down the same pipe it will flow freely.

 

Does this mean I've got a blocked breather or is it normal for the tank to be 'sealed' when the cap is on.

 

Failing that, any other suggestions as to why the second regulator in my carb system has failed?

 

 

Thanks in advance

Ross

[Obey_R 23]

If I disconnect the pipe which joins the main filler in the wheel arch, I can blow freely though the return again, I've poked a peice of wire from where its disconnected in the photo up to the filler cap and it's free all the way.

 

Where is it meant to actually breath to? There must be a opening/filter somewhere to vent to atmosphere?

 

[Anthony 1,003]

The vent is at the rear of the wheel arch sort of behind the valance, coming off the other side of the filler neck.

 

That pipe that you've disconnected is one of the breathers off the top of the tank - the other is a much smaller bore pipe that has a valve in it from memory. Looks like it that you can see just behind the pipe you've disconnected in the picture.

[Obey_R 23]

Yeah that goes to what looks like an inline filter (I know it's not, but looks like it) then to a thicker pipe which exits near the valance.

 

Right, just tried blowing down the one which exits at the valance, it connects to what looks like an inline filter which then drops to the smaller bore tubing and runs behind the main filler, down to the valve you can see in the photo.

 

I can blow down this and can hear the air coming out from the pipe which is disconnected in the photo, so this means the small bore pipe isn't blocked. Which now makes me think a) is that valve a one way valve? It would be pointless the whole piping being there if it was, surely it's meant to breath both ways? or c) everything is working as it's meant to and I was just very unlucky to have the regulator split?

 

I know it's probably top of anyones list of things to do, bit I'd be hugely greatful if anyone can try to blow down their return pipe in the engine bay with cap on and off, and see what the result is.

 

I'm obviously reluctant to just fit it all back together and hope for the best, but at £30 each I don't want to have the regulators failing reguraly.

Edited August 4, 2011 by Obey_R

[smithy 1]

you will always get some resistence when blowing down the return as it is a long hose run and then goes through the fuel pump housing.

 

I dont think you have an issue as you have checked the breather itself and found to be ok,but just to confirm what i would do is put a tyre valve in the return hose and use a foot pump to put some air down that is under more pressure than your mouth can and see if it holds or loses the pressure on guage.