Rollover valve

[Spout]

Further to my search for the source of my PPP (pesky petrol pong):

There are two breather/overflows from the tank. One from the fill nozzle (overfill/bungling hands ), and the other from the 'rollover valve' (situated inside the tank below the filler).

When the air in the tank expands (parked up, hot engine etc) which does it use to ventilate?
My guess is it's the rollover valve breather.

I have now traced my ppp to this breather. When parked in my garage after a run the petrol fumes can be seen blowing out of it (very hot engine, only a couple of litres in tank). Temporarily blocking this breather 'seemed' to reduce ppp (after ventilating garage), but there was a hell of a pressure build up after 10 mins or so.

My initial thought was that petrol must be getting into this breather at the connection in the access plate (although I checked this yesterday), but now I'm wondering if something might be wrong with my 'rollover valve'. (Pipes are all connected)

Can someone kindly explain what the rollover valve does, and how it does it? And does mine sound knackered?

Cheers......

Note: I haven't had to test the valve in a 'rollover' situation........yet

 

[BiG DoM]

Further to my search for the source of my PPP (pesky petrol pong):



Note: I haven't had to test the valve in a 'rollover' situation........yet

Maybe thats the next step... roll her over!

 

[Mick Fagan]

As I understand it the hole in the fuel filler recess is designed to catch water that seeps down during wet weather or washing. This ventilates directly to the inner wall on the fuel pump metal housing where it passes out at 90º then another 90º turn to a hose that then ventilates above the swing arm.

This has been a problem on my bike because of the water seeping down there over time it gets caught in the pipe system and starts rusting. On the last fuel filter change I forced gas welding rods through which cleared this pipe and once again the water will now safely seep down and out.

The rollover thing is something that I don't know too much about, however after looking at a spare parts picture it appears to just be a straight connection from the fuel pump metal housing and back again, with the float thing obviously cutting off fuel flowing out if the bike is upside down. One of the pipes, I think, goes to the outside via the fuel pump metal housing wall and this also vents above the swing arm.

Mick.