'86 VFR fuel pump relay question

07-15-2003, 07:54 AM

On my '86 VFR700, the fuel pump didn't seem to be working as it was starving for fuel. I could hear it "pop" just once when I turned on the ignition and that was it. I unplugged the fuel pump relay and used a jumper wire as outlined in the service manual. Now when I turn on the ignition, the fuel pump runs like crazy "pop pop pop" ect. and the bike runs great.
My question is this: Do I have to use the relay? Will my fuel pump burn up if I don't replace my relay and just use the jumper wire? Just what does the fuel relay do anyway??
Thanks,
Ed

keny · 07-17-2003, 11:24 PM

It stops the fuel pump working when the ignition is on but engine not running. So there is a risk the cabs can bleed ower.

waldrm · 07-29-2003, 11:35 AM

Ed, look at your fuel pressure sensing switch as well. The relay allows the switch to be run with smaller gauge wire; notice that the leads from the relay to the pump are heavier than the one to the pressure switch

07-30-2003, 12:33 PM

Thanks Waldrm, but where is the "fuel pressure sensing switch"? I know where the relay is but don't see a "switch". I looked in the service manual and didn't see anything there.

-Ed

waldrm · 07-30-2003, 01:03 PM

Sorry, Ed, but when you said fuel pump relay I was thinking VFR800 with FI. Don't think your bike has a fuel pump; it is gravity fed from the petcock on the left side of the tank. Check your system for blockage or pinched hoses; especially the screen inside the tank on an older bike.

keny · 08-03-2003, 10:27 PM

All VFR:s do have a fuel pump!

6ft5inch · 01-05-2006, 11:18 PM

By the way Kenny, the 1986 Vf500f is gravity fed, as in NO pump. Just FYI. I am an owner. Coincidently, the fuel petcocks for 84-85 are different than 86 too. Again, just FYI.

rc24rc51 · 11-23-2008, 02:02 PM

i have an 86 750 and the fuel pump does not run like that of a fuel injected bike. Mine just clicks a couple of times when the ignition is turned on and that's it. I don't really think your pump is bad if it runs when you jump it. Is there a fuel filter on the bike? That's the first thing i'd replace.Can you run the bike from an alternate fuel source using the pump? Just run a line from the inlet side of the pump to a gas jug and see what it does. Does fuel flow freely from the tank with the fuel line disconnected from the pump?

squirrelman · 11-23-2008, 06:00 PM

i've been using the jumper wire on my '86 700 since the relay failed in '91 with no problems.
just be sure to turn the key to OFF if the bike happens to go on its side.....

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07-15-2003, 07:54 AM	#1 (permalink)
Guest Guest Posts: n/a	'86 VFR fuel pump relay question On my '86 VFR700, the fuel pump didn't seem to be working as it was starving for fuel. I could hear it "pop" just once when I turned on the ignition and that was it. I unplugged the fuel pump relay and used a jumper wire as outlined in the service manual. Now when I turn on the ignition, the fuel pump runs like crazy "pop pop pop" ect. and the bike runs great. My question is this: Do I have to use the relay? Will my fuel pump burn up if I don't replace my relay and just use the jumper wire? Just what does the fuel relay do anyway?? Thanks, Ed

07-17-2003, 11:24 PM	#2 (permalink)
keny Senior Member Join Date: Jun 2003 Last Online: 01-03-2009 08:55 AM Location: city of Hanko, Finland North Europe - Find Me! My Ride: 1987 Honda VFR750FH, 1986 Suzuki GSX550E (wifes) View my Photo Gallery Posts: 190 Thanks: 0 Thanked 1 Time in 1 Post	Re: '86 VFR fuel pump relay question It stops the fuel pump working when the ignition is on but engine not running. So there is a risk the cabs can bleed ower. __________________

07-29-2003, 11:35 AM	#3 (permalink)
waldrm Senior Member Join Date: Jan 2003 Last Online: 12-31-2008 09:23 AM Location: SE North Carolina My Ride: '90 RC30 clone; '94 CB1000, '99 CB750, '06 599 Posts: 243 Thanks: 0 Thanked 0 Times in 0 Posts	Re: '86 VFR fuel pump relay question Ed, look at your fuel pressure sensing switch as well. The relay allows the switch to be run with smaller gauge wire; notice that the leads from the relay to the pump are heavier than the one to the pressure switch __________________ '94 CB 1000, Power Commander, Vance & Hines full system, Ohlins rear shocks, LED tail light, Thurn LED mirrors. '90 VFR with Staintune high mount and Thurn RC30 replica body kit,. CBR900 forks for the RC30 look on the cheap. '99 CB750 Nighthawk '06 599, CRG levers and bar end mirrors, frame sliders, Rizoma concial handlebars, adapters, and grips, LED signal and tail light conversion, whacked rear fender. Gave the Buell to my god-daughter; wanted her on something slow, heavy, and loud!

07-30-2003, 12:33 PM	#4 (permalink)
Guest Guest Posts: n/a	Re: '86 VFR fuel pump relay question Thanks Waldrm, but where is the "fuel pressure sensing switch"? I know where the relay is but don't see a "switch". I looked in the service manual and didn't see anything there. -Ed

07-30-2003, 01:03 PM	#5 (permalink)
waldrm Senior Member Join Date: Jan 2003 Last Online: 12-31-2008 09:23 AM Location: SE North Carolina My Ride: '90 RC30 clone; '94 CB1000, '99 CB750, '06 599 Posts: 243 Thanks: 0 Thanked 0 Times in 0 Posts	Re: '86 VFR fuel pump relay question Sorry, Ed, but when you said fuel pump relay I was thinking VFR800 with FI. Don't think your bike has a fuel pump; it is gravity fed from the petcock on the left side of the tank. Check your system for blockage or pinched hoses; especially the screen inside the tank on an older bike. __________________ '94 CB 1000, Power Commander, Vance & Hines full system, Ohlins rear shocks, LED tail light, Thurn LED mirrors. '90 VFR with Staintune high mount and Thurn RC30 replica body kit,. CBR900 forks for the RC30 look on the cheap. '99 CB750 Nighthawk '06 599, CRG levers and bar end mirrors, frame sliders, Rizoma concial handlebars, adapters, and grips, LED signal and tail light conversion, whacked rear fender. Gave the Buell to my god-daughter; wanted her on something slow, heavy, and loud!

08-03-2003, 10:27 PM	#6 (permalink)
keny Senior Member Join Date: Jun 2003 Last Online: 01-03-2009 08:55 AM Location: city of Hanko, Finland North Europe - Find Me! My Ride: 1987 Honda VFR750FH, 1986 Suzuki GSX550E (wifes) View my Photo Gallery Posts: 190 Thanks: 0 Thanked 1 Time in 1 Post	Re: '86 VFR fuel pump relay question All VFR:s do have a fuel pump! __________________

01-05-2006, 11:18 PM	#7 (permalink)
6ft5inch Junior Member Join Date: Jan 2006 Last Online: 11-19-2006 11:06 PM Posts: 9 Thanks: 0 Thanked 0 Times in 0 Posts	By the way Kenny, the 1986 Vf500f is gravity fed, as in NO pump. Just FYI. I am an owner. Coincidently, the fuel petcocks for 84-85 are different than 86 too. Again, just FYI.

11-23-2008, 02:02 PM	#8 (permalink)
rc24rc51 Member Join Date: Nov 2008 Last Online: Today 03:44 PM Location: Liberty SC My Ride: 86 VFR750 00 RC51 07 CBR600RR Posts: 33 Thanks: 0 Thanked 2 Times in 2 Posts	i have an 86 750 and the fuel pump does not run like that of a fuel injected bike. Mine just clicks a couple of times when the ignition is turned on and that's it. I don't really think your pump is bad if it runs when you jump it. Is there a fuel filter on the bike? That's the first thing i'd replace.Can you run the bike from an alternate fuel source using the pump? Just run a line from the inlet side of the pump to a gas jug and see what it does. Does fuel flow freely from the tank with the fuel line disconnected from the pump?

11-23-2008, 06:00 PM	#9 (permalink)
squirrelman Senior Member Join Date: Jul 2006 Last Online: Today 03:29 PM Location: barf-a-load, ny - Find Me! My Ride: '86 VFR 700Fs (3)/ '97 VFR 750F/ '88 NT 650 HAWK (3)/ '86 Yamaha Radian/ '66 Yamaha YL-1/ '88 VTR 250 (2)/ '73 CB 125 View my Photo Gallery Posts: 973 Thanks: 7 Thanked 36 Times in 36 Posts	i've been using the jumper wire on my '86 700 since the relay failed in '91 with no problems. just be sure to turn the key to OFF if the bike happens to go on its side..... __________________ " Goin' to Hell in a bucket, but at least I'm enjoyin' the ride....... " "It's no use, mate, the bottom's fallen out......."

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