87 VFR 700 Fuel Pump...not pumping.

Discussion in '1st & 2nd Generation 1983-1989' started by vfrf2, Mar 29, 2010.

  1. vfrf2

    vfrf2 New Member

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    Before I go off half cocked and buy a new fuel pump, I'd like to make sure it's hosed.

    I jumped the black/black-blue wire to test it. I can hear the motor going, but nothing is coming out. Lines are hooked up correctly, I see gas in the fuel filter on the inlet side, no pinches in the lines etc, etc. Anything else I can try, or is it time for a new one?
     
  2. Dukiedook

    Dukiedook New Member

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    I don't think these are rebuildable, probably need to start looking for a replacement.
    Anyone know of a newer/more reliable substitute fuel pump you can use in this situation?
     
  3. Rollin_Again

    Rollin_Again Active Member

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    You should be able to bypass the fuel pump altogether and use a gravity fed system. The only modification you may need to do is alter the petcock so that it doesn't require vacuum to be actuated. Jamie Daugherty can give you more details on how to do it.

    Regards,
    Rollin
     
  4. vfrf2

    vfrf2 New Member

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    I know I can go with a gravity feed setup, but...I'm just planning to run it stock with the fuel pump. Are there alternatives to the oem replacement at $150?
     
  5. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    I'm not sure that gravity feed was recommended for the larger motors, only the 500?

    I'd recommend that you make sure it isn't a petcock problem. put the pickup line for the pump in a small fuel can and see if she'll pump.
     
  6. TOE CUTTER

    TOE CUTTER Mullet Man

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    A fuel pump is a must have item for gen 2 , it will only gravity feed until the fuel is level with the petcock. About half a tank and does a rather poor job at that. Have you tried to blow throught the pump to see if the valve is stuck or stuck open?
     
  7. vfrf2

    vfrf2 New Member

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    I'm getting fuel all the way through. Gas comes out of the petcock, goes through the line through the filter. Free flowing all the way to the inlet side of the fuel pump using reserve, on, and turns off when I throw it to off. Now I'm just getting a click every time I jump it. It's not even running as it had before. Toasted fuel pump...
     
  8. squirrelman

    squirrelman Well-Known Member

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    IF it clicks, it's alive, but you could have a bad diaphram or debris in either one of the two one-way valves.

    If fuel is going in, try running output side into a can and check volume of flow.

    Pump does NOT run continuously as it senses pressure and turns itself off as long as fuel pressure is built up in outlet side.
     
  9. yllibllik

    yllibllik New Member

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    i had the fuel pump diaphram go bad in my 86 and i picked up a low psi (2-5psi) universal auto fuel pump from auto zone and direct wired it to the hot line going into the fuel pump relay and a negative to the battery. had to bypass the relay because the relay wasnt allowing a full flow of current into the pump which it needed to work. as long as you turn your bike off when your not running it,no probs, as the relay only regulates the current to the oem pump to keep it from flooding the carbs.works like a dream, and it only cost me 35 bucks and 15 min work.if you have to test electrical systems tho i recomend you disconnect the pump's power or you will overflow the carbs.
     
  10. squirrelman

    squirrelman Well-Known Member

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    Glad your generic pump works, but you have a few misunderstandings of the system. Have u read the service manual ??

    OEM pump will never flood good carbs if carbs are good.
     
  11. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    +1 Properly functioning needle/seat and floats. A stock pump that doesn't generate too much pressure will "dead-head" when the needle/seat close.
     
  12. yllibllik

    yllibllik New Member

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    with an oem pump it shouldnt overflow unless the carbs are dirty i agree. but i was talking about if he replaces the oem with the generic. the generic is a few pounds of pressure over the oem rating, and will flood the carbs if the bike is powered without starting the engine.
     
  13. yllibllik

    yllibllik New Member

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    from what i understood is that the relay supplies power to the pump only when the ignition is firing, to prevent flooding in case of mechanical probs so there isnt a fire. but only supplies power when engine revs are at a determined speed. i may be wrong but i dont know of any other reason to regulate power to the pump to run only when engine is firing other than a saftey measure. the pumps will work just fine without a relay, but the relay is there to prevent flooding in case of malfunction somewhere.
     
  14. squirrelman

    squirrelman Well-Known Member

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    Seems you might not understand.....power to pump whenever engine is turning.
     
  15. yllibllik

    yllibllik New Member

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    im pretty sure that is what i just said. my english may not be perfect but im sure that i said the relay only supplies power to the pump when the engine is running. i will repeat. the relay regulates power to the pump when the engine is running.r.i may be wrong but i dont know of any other reason to regulate power to the pump to run only when engine is firing, other than a saftey measure. the pumps will work just fine without a relay, but the relay is there to prevent flooding in case of malfunction somewhere.like an accident.seems i didnt explain myself well. i was only saying that he does not need the relay, because its only a saftey measure, that is not necessary to function. it is there to prevent fuel overflow in case of malfunction.if there is malfuntion the oem pump can indeed flood the bike and is dangerous so there is a relay to protect from overflow. if the carbs are empty than the pump will fire once when the ignition is pressed, but the pump will not run because engine wont spin fast. it has to spin at a certain speed.that is why you have to jump the oem pump when the carbs are empty its because of the relay. if all it took was a turning engine you could just hold down the ignition for a few seconds at a time until it filled.this is why it is called a fuel cut relay.it cuts fuel supply in case of mechanical problems. i dont know one wrong thing i said, but maybe that i didnt make myself more understandable.im sure i didnt missunderstand.i dont remember saying that the oem pump would flood a working system, only that the purpose of the relay was to protect against flooding and fuel overflow, which is true. and that the relay only powers the pump when the engine is running, which is also true.and that attaching a generic impeller pump with the psi rating i did and bypassing the relay you will flood the bike if it is not powered down, which is true.
     
    Last edited: Mar 30, 2010
  16. vfrf2

    vfrf2 New Member

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    Back in the fall when I was having fuel issues, I was jumping it to verify that it was working, with no line connected to the carbs. It pumped gas into my jar every time. I would expect to see the same results this time. I did try blowing very low air pressure through the fuel pump, it didn't help.

    The entire thing was gone through last Fall. Carbs removed and cleaned etc. New petcock was installed, I also had some other issues and had to replace the fuel relay (new OEM unit).
    I'm probably just going to install a new OEM fuel pump if need be. My past experiences with jerry rigging things like this typically cost me more $ in the long run, so...oem seems to be the way I'm leaning.
     
  17. squirrelman

    squirrelman Well-Known Member

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    <<<<>>>>

    OK. man....you do understand, but i was referring to this statement :

    "........ but only supplies power when engine revs are at a determined speed. i may be wrong....."
     
  18. captb

    captb New Member

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  19. dbmcd

    dbmcd New Member

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    Why don't you tell him what he doesn't understand...YSS. You're not much help.

    Sent from my SM-G900P using Tapatalk
     
  20. squirrelman

    squirrelman Well-Known Member

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    His first post and he's already kikkin my ass !! :livid::pig:


    Pump only supplies fuel when it senses lowering level in float bowls, not any predetermined engine speed !
     
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