VFR700 Resurrection

I've got an 86 VFR700 that had been sitting up for the last couple of years, outside but almost always with a cover. I took off the carbs, degunked them, and dropped them back in (which was just as much of a PITA as everyone says). I also derusted the tank and put a new fuel line (from the tank to filter) and new filter in.

Soooo, when I try to jump her off, the engine just won't catch. I notice the fuel filter isn't filling with gas so unhook it from the fuel pump and then it fills. I hook it back up, check the fuel pump's electrical connection (dielectric grease it too), and still no go. I check the fuel line from the pump to the carbs and it's still dry, I suck some gas into the line (and my mouth ), hook it up again and still nothing.

In a last ditch effort to isolate the problem, I bypass the pump and filter altogether by going straight from the tank to the carbs. With the choke all the way on I start to hear a bit of combustion I think, but the starter's still doing most of the work. I'm not even sure if a gravity feed would work on this bike though.


Is the fuel pump dead? I don't hear any priming, but I'm not sure if I'm supposed too.

Any ideas? I'm dyin here

 

Not sure about the 700 but on my 500 you should be able to hear a click if you have the key on and flick the kill switch back and forth. I'm pretty sure you can set the 700 up with gravity feed. My 500 runs better without a pump just make sure you use that filter.

 

I am going through a similar situation on mt 87 700. I bought it after it set for 3 years. one of the previous owner replace the fuel pump with a Puralator universal pump from an auto parts store. It work but tends to load the carbs up and uses more fuel. I tried gravity feed but the bike didnt run well at all.
Im am assuming (though I havnt gotten anyone to confirm) that the stock fuel pump should run untill the system have between 2 and 3psi and then shut off.
Also on of the guy parting out a 700 on this forum has a couple of these for sale. He was wanting 50 plus shipping for both. I was going to buy both and have a spare but if you need one let me know. I also was told that an 83 honda civic 1.3L fuel pump would work...... I dont know that to be fact though.

 

Yeah, I have the feeling that the gravity feed would at least make it run rough if it hadn't been so long since it last ran.

I'm hoping to at least get it cranked in the next couple of days.

Kingsnake, shoot me a pm or email when you want to do it. I'll go in half with you. I'm leaving town in a little under a month, so I'll need it before then though.

Thanks for the help guys

 

I Can tell you for a fact that V45 magnas and sabres along with V65 magnas and sabres run perfect with the civic fuel pump. It shuts off around 3 psi.

 

same electrical connection with the civic fuel pump? Any mods needed?

 

not sure what your seven hundred uses but the last civic pump I saw used 2 bullet style connectors

 

Drain the carbs and see if any fuel comes out. If the float bowls have gas, then the bike should start. Focus on starting the bike first. Worry about the gas delivery later.

 

No fuel in the bowls, so no starting. Needed to take care of fuel delivery first. I've since sold her, but wanted to throw it out there that I don't think a gravity feed will work on the 86-7's because of the tank/carb situating (i.e. fuel isn't high enough in relation to the carb to provide necessary fuel pressure.

Thanks for the help though guys.

 

If you leave the old style pumps sitting around the have a nasty habit of corroding the points in the back of the pump and making them stick together and the pump don't work maybe that's what happened

 

I know for a fact that an 86 VFR700 will run with gravity feed. I got mine started that way. The bowls will fill with gravity feed, its just slower than with the pump so it wont work well on the road. If your bowls arnt filling check the lines and make sure they arnt kinked or clogged anywhere. I do need to find out more about the civic fuel pump tho. I have a pump on mine that is not factory but I dont know what it is, or what psi its running at.
Good Luck!

 

I was thinking of getting a spare pump and the best I can find other than the civic pump is this on Ebay. Looks like a good replacement possibility, I emailed him and demensions are very close and it's 3/8 lines, guy sells alot of them with good feedback. Looking at the rear cover it looks like the oem Mitsubishi Pump...maybe a copy.

LOW PRESSURE FUEL PUMP 12 VOLTS UNIVERSAL 2-4 PSI:eBay Motors (item 320420134331 end time Sep-08-09 13:18:33 PDT)

 

Fuel pump is powered via a fuel cut off relay which only operates when engine turning above 1000 rpm.

Not a problem normally as engine will start on fuel in carb bowls. However if carbs are empty then engine will not spin fast enough to operate relay. Simplest fix is to remove connector from relay and short two wire with Blue bands on them.

Did get an '89 VFR750 home over 150 miles on a gravity feed conversion after fuel pump failed at 59,983 miles. (blew the 60,000 trouble free miles claim).

However if you haveit started I am assuming you know have fuel to carbs. Have you checked all four bowls are full? - release drain screws and check for fuel running out.

Unfortunatel modern fuels are a pretty nasty brew and tend to form a film in carbs blocking small air jets etc.

Try adding some Injector cleaner to fuel tank then run engine and see if that improves thngs.

 

I grew up around motorcycles. My first job was as a mechanic in a HONDA dealership.
MAny different kinds of bikes and none of them had fuel pumps. Only gravity feed and the carbs have not changed much. Some newer ones have accelerator pumps like a car but thats it.

I recently had a Kawasaki 1500 v twin and built it into a chopper. New frame everything.
I eliminated the fuel pump and it ran perfect.
In 1984 was the first year for Kawasaki to have a fuel pump and then late in 1984 they switched to fuel injection which does require a fuel pump.
I believe the early carbed models just had the fuel pumps wired in to be ready for the fuel injection thats all.

 

Carbs are high in relation to the tank position on some V4s I could see fuel starvation being possible when tank is low on fuel or in turns and certain conditions.

 

uhhhh........OK