Vfr750 fuel pump issue

Hi all

Restoring an 88 VFR and the fuel pump was dead as was the relay. Got a second hand one and fitted last night. Pump runs on ignition but does not stop. Bike won't fire and I think it's due to lack of fuel.

Any advice appreciated.

Cheers,

Chris

 

Yeppers !!

A pump that's clicking like mad and won't stop is most likely not getting any fuel from the tank is what me dear ol' auntie always said.

 

Hi Squirrelman

I borrowed a pump off the wife's CBR and that ran the bike ok, also changed the fuel filter in case there was a blockage

 

If the bike has set up for a long time, then the old fuel in it turned to varnish and gummed up the old fuel pump--plus the tube-end screens inside the tank, the petcock internals, all rubber tubing, the inside circuits and passages of the carburettor. You may be able to soak the old fuel pump in a bucket of pine-sol to breakdown the varnish, then use carb cleaner spray to clean it out. Good luck and cheers...

 

Hi Kenny

Many thanks for the advice, will try to soak over the weekend. Got some carb spray today as well.

Cheers,

Chris

 

Starting fluid is your friend

 

This is the confusing thing. I fitted the pump off the wife's CBR and the bike runs fine, it's just when I fit the original VFR pump back on, clicking and no fire :-(

 

Pump has 2 reed-type checkvalves, one in/one out, and they can be tested by blowing air.

You should be able to blow air into intake valve but not suck any air out/same with output side but opposite: air should be suckable through the valve but no air should be blowable in. It's concievable that varnish, rust flakes or other debris have lodged in a valve.

Clean the pumping section with water + Simple green* (or similar) and use long hoses for blowing/sucking.

KennyBobby is one surely among our most informed and astute members, and i don't believe he would recommend soaking the pump's electrical elements in anything, so he must have meant the PineSol treatment for the pumping section ONLY(?).


* Not a compensated endorser.

 

Not exactly. Besides being highly explosive, it strips a necessary layer of oil off the cylinders, pistons, and rings, causing some scuffing damage to all of them.

 

Hi all

Many thanks for all your values advice, the pump was only pushing 0.5 psi and not the recommended 5psi. It would appear that the bellows was to blame :-(

Again many thanks all