Fuel pump down? Help!

Discussion in 'UK Motorcycles' started by Sleepy, Feb 26, 2006.

  1. Sleepy

    Sleepy Guest

    I need some help diagnosing which bit needs replacing to sort the lack of
    fuel being pumped on my CBR600F-W.

    With all parts in normal positions except open ended clear pipe on pump
    outlet, crank engine, no fuel.

    Detach pipe from pump inlet, fuel everywhere!

    Remove rear cover from pump to reveal set of contacts, spring etc.: crank
    engine, it sometimes does one "jiggle" with a little spark from the

    Fuel pump relay can be felt to clunk when starter button pressed and

    So: do I replace the pump or the relay or something else?

    or can anyone who knows about these things suggest any more tests to do?

    Is my habit of turning off the petrol tap about half a mile from home (to
    drain the carbs) likely to be the cause of the failure?
    Sleepy, Feb 26, 2006
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  2. Sleepy

    Stuart Gray Guest

    WTF? Why?
    Dunno about the rest. Or the above actually.
    Stuart Gray, Feb 26, 2006
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  3. Sleepy wrote
    A cause of fucking wonder. Which clueless **** told you to do that
    and fix your sig.
    steve auvache, Feb 26, 2006
  4. Sleepy

    Sleepy Guest

    Can't remember who - something about carbs gumming up if left for a few
    weeks. I do often have to leave it unridden for weeks at a time (awaits
    Sleepy, Feb 26, 2006
  5. Sleepy wrote
    Basically it is all bollox.

    There is a school of thought persisting from years ago that says you
    should drain all the fluids if you are putting a vehicle into storage
    for a LONG period of time. Technology has pretty much made this
    irrelevant except for things going into long term storage in a very real
    steve auvache, Feb 26, 2006
  6. Simon Gates wrote

    It'll be working over speed on no load surely?

    I didn't know they were rotary pumps, I thought they were solenoid
    driven diaphragm type things. When did they change that then?
    steve auvache, Feb 26, 2006

  7. Whaa-aat?

    ****, how clueless can you get?
    The Older Gentleman, Feb 26, 2006
  8. The Older Gentleman wrote
    Dunno, do you want to sound him out on his electrics?
    steve auvache, Feb 26, 2006
  9. Sleepy

    Sleepy Guest

    Looks to me like solenoid & diaphragm, with contact arrangement not unlike a
    door bell.
    Sleepy, Feb 26, 2006
  10. Sleepy wrote
    Do you know how to stroke a contact spring to the right looking curve
    and then put tension in it and straighten it all in one go with a single

    If the answer to the above is no then get man in who can and still be
    prepared to buy a new pump. Second hand should be fine.
    steve auvache, Feb 26, 2006
  11. Sleepy

    wessie Guest

    steve auvache emerged from their own little world to say
    It was a solenoid jobby that I replaced on my 1988 VFR750. The "relay" was
    a solid state thing and the faulty pump took this out. My assumption was
    that the pump emptied under the normal spring load and when the solenoid
    actuated to refill the chamber it all went titsup. Not enough movement from
    the piston meant the full sensor was not triggered and the solenoid was
    left permantly on, which burnt out the SSR.

    I was not in the habit of turning the fuel tap off whilst riding home but I
    would imagine that the relay failure I describe could be induced, maybe
    over the course of time, by starving an actuated solenoid of fuel.
    wessie, Feb 26, 2006
  12. Sleepy wrote
    It's that time of year.

    steve auvache, Feb 26, 2006
  13. Sleepy

    Sleepy Guest

    Lectrics I can do - mechanical numpty (you didn't need telling, did you).
    Sleepy, Feb 26, 2006
  14. Sleepy

    raden Guest

    Mine's been parked up for the past two months

    put the battery back in yesterday - turned it over a few times

    vroom bangity vroom no probs
    raden, Feb 26, 2006
  15. wessie wrote
    More likely in this case though is that the thing is pumping against no
    back pressure far, far too often and overthrowing or something similar
    which is causing it to fail young through repeated unreasonable
    mechanical stress.

    But then again he hardly rides the thing so it is probably almost brand
    new anyway so it might not be that.
    steve auvache, Feb 26, 2006
  16. raden wrote
    You was lucky is all.

    Statistically speaking there is still petrol left in the tank from it's
    very first fill and if the doomsayers are right you could be in dead
    trouble with that if ever it gets out into the carbs.
    steve auvache, Feb 26, 2006
  17. Hmm. Sounds like a duff pump to me, but don't buy a replacement on
    *that* judgement. It's just my best guess as to what to suspect and
    confirm, y'know?
    Yes. Set the pump up so it'll feed petrol from the tank into a
    petrol-safe bottle rather than the carbs. Wire it directly to 12Vs
    rather than via the relay. If you've got any sort of workshop manual,
    it should at least have enough of a wiring diagram to help you work out
    how to do that. The pump should pump merrily away. If it doesn't, it's

    Further checks on the relay? For that, if I were you, I'd buy a cheap
    digital multimeter (they've even been known to flog 'em in Aldi) and
    check that the relay is operating by testing the pump switching contacts
    for continuity when it's supposed to be `on'. Then check that you've
    got the `12V relative to the bike's frame' feeding out of it to the wire
    that goes to the petrol pump.

    If that's in the clear, wire it up to the petrol pump and see if you can
    measure the voltage applied to the petrol pump when the relay is `on'.
    If things are okay, you should see about 12V (or higher if the engine's
    running). It's possible for a faulty relay to have relatively high
    resistance contacts which show as `make' and `break' on the multimeter,
    but it doesn't take much resistance with some higher powered loads to
    put an end to the idea of the machinery working properly.

    I've never bothered to find out how much current any bike petrol pump

    btw, my VFR750 stopped recently with fuel starvation. Turns out that
    the fuel filter had developed an air-lock. It was dark and raining and
    late so I got carried home on a truck. Fixing the problem - once
    spotted - was merely a matter of tipping the fuel filter *thataway*
    until it filled up with petrol again, and I've had no trouble with it
    since (could have done it on the roadside easily if I'd got as far as
    spotting the trouble - but would you fiddle around to fix your bike in
    the cold, wet, and dark when you've got breakdown cover, a mobile phone,
    and can see a warm and inviting hostelry over the road? I thought not.
    Me neither). What and how and er? I dunno - but strange things happen
    when petrol's involved.
    You only really need to do that if you've got a pre-mix two-stroke -
    pre-mix means `You put a measured amount of oil in your petrol tank'.
    Two strokes need this oil for engine lubrication. Four strokes don't.
    Some two strokes have an oil tank and pump to pump oil in to the fuel
    stream on the fly (there are other various ways of doing it). If you
    let a pre-mix two stroke carb evaporate dry and you're using, say, 1970s
    petrol and oil, it'll be really horribly manky. Leaving a carb to
    evaporate dry repeatedly with 1980s petrol (and no oil in it) never
    seemed to cause my CZ's carbs any problems.

    For those who deride you for being clueless - oi, you lot, haven't you
    forgotten what it was like when you hadn't learnt everything you've
    learnt over your decades of exposure to motorcycling?

    Rowland McDonnell, Feb 27, 2006
  18. Sleepy

    Muck Guest

    It takes more than a few weeks to gum things up, more than a few months
    in fact.
    Muck, Feb 27, 2006
  19. True. Mind you, in them days we were faffing about with rather more
    basic machinery.
    The Older Gentleman, Feb 27, 2006
  20. Sleepy

    Sleepy Guest

    Thank you Rowland. I was wondering if that approach was valid, but unsure
    if there was any electronic magic in the relay that would mean wiring 12V
    direct to the pump would be useful or result in a "kaboom" scenario (petrol
    & too many amps).

    Even cheaper multimeter than Aldi - I'll borrow one from work today.
    Sleepy, Feb 27, 2006
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