morning all Should there be a constant stream of fuel coming out of the air separator in the tank? Only noticed this a few weeks ago and can’t be sure if it’s always done this. Part is No. 17 in diagram.
I don't know the answer to the question but am interested in it for future reference, but how on earth did you notice and observe that Ian?
Hi Paul. Because the fuel level at the time was lower then the separator, you could see it. I’d had the bike running for about 10 mins out in the sun and by chance lifted the fuel cap to check for pressure. Noticed it then and every time i’ve run the engine since it’s done the same. Ian
I would venture to suggest the answer to your question is yes. How else would you separate any air bubbles in the fuel line if the means to do so was a closed loop ? Andy
Cheers Andy. Just confirmed by Lee from Moto Technical. It’s normal but most people won’t notice it unless you have a carbon or similar tank. The reason being the fuel cap aperture on the carbon tank is wider and more shallow so you can see the separator. You can’t with a steel tank cause the fuel cap hole is too small and deep. Thanks, Ian
Which part of the air seperator could you see the fuel coming out? (I've been wondering what that thing was - should've looked in the parts manual!). I ask because I've got a misfire on my 996 and I can see spray towards the front of the tank quite high up, as though coming from the right angled tube at the top of the seperator, but I've got a regular tank so cannot see clearly and couldn't lay my hands on a small mirror. Now I'm wondering if only air should come out, at that point, and the fuel go back down to the pump via tube 16 ?
I agree .... Fuel from the return line to the tank ( still under some pressure ) enters the separator via pipe 19 , and any fuel with bubbles in it will rise up and exit at the top . The fuel without bubbles is returned directly ( via pipe 16 ) to the inside of the scavenger basket/filter ..... ( underneath the fuel pump ..... marked as 20 on the diagram ) . So I'd expect to see some fuel coming out from the top of that separator unit It's not the most advanced bit of engineering in the world , but I guess it get's the job done ..... I tried to post the diagram of the tank itself , with the two thick tubes , but I'm useless at adding photos etc.
