Hi all, so on Monday I noticed a gasoline smell when standing still on the bike. I first thought it was maybe a patch on the road even though I didn't see anything. At home I saw the fuel pump seemed to be pumping gas out of the drain hose and created a little puddle on my swingarm.

I checked the pump and it was leaking from beneath the mounting rubber sleeve thingy and removed the pump. The little black cap didn't seem to seal very well (looks like it had been fixed before with somehot glue behind the o ring... I then used some silicone gasket stuff to seal that up but it still kept leaking (since I assumed it came from the black cap side). I checked it and it was leaking from the machine pressed side of the pump. I am now wondering it it's the pump itself that's faulty or perhaps just the little relay behind the black cover. The pump doesn't seem to shut off and just keeps on pumping and pumping till it's overpressured and leaks at the pump itself. It even hissed at me once. What does that relay do exactly (I know it's the cut off relay but not sure how it works)? Does it regulate the pressure and if so, how does it do it? I've seen a fuelpump repair kit for about 20 bucks (the relay), does anybody know if this would fix my problem?

I have an F4, the leak seems to be quite uniform around the machine pressed part (see pic), it primes and pumps fine but it just doesn't stop. I could buy a pump but would rather just spend the money on the relay if that would fix it.



I've been running it gravity fed but I feel feel it's starving for fuel sometimes. I've also ran out dry three times (on gravity fed) of which one on the highway (no fun) Any ideas?

 

Anyone?

 

First of all under the black is a set of contact points which pivot on an overcentre mechanism to open and close.
Points closed completes the circuit through the main coilof the pump(the cylindrical part between the cover and the crimped pump itself) When the coil is activated it will pull the rod joining the pump diaphragm and the overcentre mechanism up to the top.As the rod overcentres the points open,the coil de-energises and the spring above the diaphragm pulls the rod back down and the points close again and start the sequence again hence "click click click"
The fuel should only be on the lower side of the diaphragm being drawn in when the diaphragm lifts and pushed out when the spring returns the diaphragm to the start position.There are little spring loaded valves in the pump body where the suction and delivery connections join the pump body.
Inshort if fuel is leaking round the crimped area where the pump joins the coil assembly the pump is toast.
This type of electric pump work on the pressure balance between the diaphragm return spring pressure and the pull of the electrical field in the coil when energised so that any leak will cause the pump to run continuously
Here endeth the sermon hope it clears up what is going on .

 

Thanks TK! I found my issue via Google a few times but without any answers.