could it be the fuel pump/relay?

Discussion in 'Mechanics Garage' started by vfrkevin, Nov 5, 2013.

  1. vfrkevin

    vfrkevin New Member

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    So, last time i was here i had wonderful assistance in getting the carbs off my bike and of course the round of cleaning so eloquently set forth in the carb cleaning guide. However, i described another problem. The bike keeps bogging down and quitting. The response was clean the tank, clean the lines, replace the fuel filter.... but all to no avail because the problem keeps happening. The bike quit on me 3 times in 15 miles on my way home from work this morning. Sigh.....

    Could the problem be the fuel pump or the relay? I mean seriously, it bogged down and quit 3 times when it's usually just once per ride.

    Any thoughts on the matter? Should i order a new pump? (oem is 130 at hondaparts-direct website) or are there alternative pumps (read after market and cheaper) available as options?

    I appreciate any advice on the matter.

    And i already know that gravity feed is NOT an option for my 86' vfr700f ;) i already read a bit about that problem lol
     


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  2. squirrelman

    squirrelman Member

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    Eliminate any possible pump relay problem using the bypass wire at the plug as described in your FSM. :cool-new:

    Once the relay is out of the circuit it's easy to test pump performance.
     


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  3. vfrkevin

    vfrkevin New Member

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    ok, so from snippets i have found across the web, if my understanding is correct, the pump itself has a sensor that tells it when to shut off because the float bowls and lines are full. which means that the relay is only to stop the pump in case of a tip over or accident and the bike is still on. Does this mean i can safely operate/ride with a bypass in place since i do not have a graduated beaker or other fluid measuring device to test pump flow? Hopefully this is ok since i gotta get to work soon...lol and hopefully this will give me a good idea of what my little horsie needs.
     


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  4. vfrkevin

    vfrkevin New Member

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    UPDATE

    so last night i grabbed a piece of wire and tried to run a bypass....but, well, rider error. It quit on me about a mile and a half into my ride to work. I adjusted it and didn't have any more problems. This morning as i left work i re-worked the bypass to make it a bit more solid of connection and i didn't have a single issue on the way home. I will test the flow as soon as i can get a glass beaker for that purpose. if everything rides well and no further sudden stoppages at the side of the road then i will prolly order a new pump relay.

    as an observation the sound of the engine was a bit higher pitch on the way home, which, hopefully means it is now getting sufficient fuel. There was no overflow, gas fumes or other indicators that fuel was escaping the carbs or elsewhere.
     


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  5. squirrelman

    squirrelman Member

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    Not quite.

    The relay is activated by power the cdi sends to an ignition coil and keeps power going to the pump as long as the engine is running. What senses that the pump needs to pump more is a spring behind the diaphram that pushes a shaft into a position that moves the armature attached to the electrical points inhto the position that activates the pump. Simple, right ??

    Relay can safely (IMO) be removed entirely, and i have that setup on all my Honda bikes cuz i've had too many relay failures over the years. Just make sure the jumper wire is insulated and doesn't touch ground.
     


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