85 vf500 fuel pump issues

Some of you may recognize me from my intro thread. I said I'd be asking for help, didn't I?
I seem to be having fuel pump issues. It seems like the fuel pump is running very sporadically. It'll work for a minute and then a minute later out doesn't. The pump is also getting very warm to the point of being too hot to hold for any length of time. I've tried two pumps and I think both do it. Any suggestions? Advice is definitely appreciated.

 

your gonna get three answers 1) is F it you dont need the fuel pump just run it gravity feed.... 2) find an aftermarket fuel pump... 3) clean the contacts on the fuel pump... have you checked your ground?

gravity feed is nice for the first half of the tank. 2nd half..not so much (in my experience) mt fuel pump on my 68 went out and I bought an aftermarket fuel pump 2-3 PSI from auto zone (Mr. Gasket ) haven't had a fuel pump problem since.

 

Small update: PO also gave me what he believes to be a750 pump which I just put in. bike ran with no problems for 5 minutes and the pump was not hot at all. Just bad pumps?

 

I've run gravity feed on all of my VF's for many years without any problems. I think the "second half of the tank" and "not all of the gas will come out" are myths. When people have a problem they will remove the pump and still have problems - then they make up a story like this about gravity feed. The truth is probably that the pump was not their problem in the first place and something else is the reason the tank won't drain all of the way (most likey the petcock or tank vent). A low pressure pump like the VF's were equipped with from the factory does not pull the fuel out of the tank - gravity feeds the pump.

Belgarion - switch to gravity feed and see what happens. If you still have issues you try looking elsewhere. My guess is that your petcock vacuum diaphragm is bad. What you describe is a typical failure of that part. Go the How To section of my site for details on how to fix it. Good luck!

 

the fuel running through the pump it what cools it ... not enough fuel running through it it will get hot

I'd start with the strainer & petcock.

 

Last night when I had stuff apart and put the 750 pump in I took the stem things off the petcock. Like I said, seems to be running fine now. If problems persist I will try gravity feed.

On a different subject, where is a good place to buy parts? I think I need some new brake pads.

 

Today i went to start the bike again and had the same issue. >.< So I decided to run it gravity feed. Seems good now. Lol ridiculous. whatever. If I decide to run a pump in the future I'm going to get some genetic one off summit racing or something like that. The thing that's bothering me now is the choke. At times it has to be fully closed, others fully open to start. While idling, the motor sometimes acts like I've been moving the choke when I haven't touched it. Is this a common problem?

 

Glad this worked out.

Regarding the carburetors, have you removed the set and cleaned/inspected all the circuits? Do you have new carburetor 'boots' on the bike?

 

I haven't touched the motor yet.

 

Cleaning the carburetors and ordering a new set of boots should be on the clipboard then.

Lots of info here on this, but if you are diving in, Mike Nixon's book on rebuilding V4 carbs is a great read as well.

 

I am SO sorry for suggesting that your way was wrong..as I said "in my experience" forgive me I must have been wrong with MY bike which is what "in my experience" is suggesting... and no there was nothing wrong with the petcock or anything else MY problem was the fuel pump, and it was fixed by replacing it with an aftermarket fuel pump...