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749 Problem

Discussion in '749 / 999' started by 2 easy, Dec 29, 2016.

  1. so my 749s would not start the other day , ( is kept in warmed shed with optimiser on ) , showing bat at 12.4 , fitted new fuel relay thingy , new battery and Ex leads all within last year . tried again this morn with battery showing 12.4 and still nothing, spinning good but no fire , tried a few times getting no where . about to give up thot, will try one more time,, this time when i turned key i heard the " woosh ", obv some priming thing which i had not heard before ( but seemed to remember i should be ) ,, sounded s if it was pumping about a gallon throo !!,, this time i just knew it was going to start and sure enough 2 r 3 turns and bursts into life,, great,, ran gently for 5 mins until warm then turned it off,, tried again , altho no woosh sound it did start but only for few seconds and started coughing out,, tried again , still no priming sound and will not start,, tried key on / off few times still no noise,,, fkd again !!,, cant believe it is the relay again after so soon,, really cant be bothered striping it down again tho i did re position it as advised , but still gonna be a bloody hassle,, any other things i should try, tried giving the fuses a shake tho cant seem to get them out easy and dont want to force, do they just pull straight out or is there a trick,, any help you 749 999 ers pls ..
     
  2. Check the lead to tank is plugged in properly(unclip and re connect with a squirt of WD).
    Fuel pump relay is next port of call, behind battery box unless its been relocated. Interchangeable with headlamp relay. £3 new.
    4pin 12V 20A normally open.Put it in rubber glove finger to protect from road crud. image.jpg
     
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  3. thanks for your help there mate , ( see within post " fuel relay thingy " ) i have already fitted a new relay , and yes been in the electric box and refitted the heat shield and re positioned the relay :Banghead: , what fkn pia that was , dont want to have to do that again, keen now in checking the connection you mention, where is it and how do i get at it, what does it look like , is it seat etc off and lift tank, ( done that as well and dont want to do again if poss ) alas i am suspecting the pump thingy its self,, hope not. thanks again mate , app.
     
  4. Under the tank. 4 wire(?) plug connector. Undo seat fixing bolts and lift seat and tank together from back a few degrees and prop it up a couple of inches if you need more access. Its rear rhs of tank iirc. Mine wasnt clicked together properly after service once, causing intermittent pump fail. Scarey!
     
  5. thank you , will try that.
     
  6. Are you using the fast idle?
     
  7. occasionally, , but the priming should come on before i even turn it over, ta
     
  8. I believe it should, but I've never had a 749. Multimeter time?
     
  9. it does, well every time it starts it does, but when it doesnt it doesnt,, i dont have nor know how to use a multi meter, but i can add 2 and 2 ,, i even know before i even press the button whether it is going to start or not !! thanks may eventually get someone round with a multi meter .
     
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  10. If you get a multimeter on your fuel pump connector (loom side), it will show whether you have power to the pump when you turn the ignition on. I'd be doing this before I invested in a pump.

    A multimeter isn't expensive and a tool everyone should have in the garage / shed.

    How to Use a Multimeter - learn.sparkfun.com
     
  11. yea i know, thanks, i have been intending on investing in one for some time , just dont have any confidence when it comes to electickery !! ,, would be more inclined just to short against the frame or hot wire the pump !! ,, but prob not a good idea :Banghead:
     
  12. With fuel involved, probably not. :Wideyed:
     
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  13. well thanks for the help all,,,,,,,,, problem no more ( for now ) , starting every time today,, only explanation is that i did not leave the heater on all nite so shed a little cooler this morn , can i be " pampering " it just a little too much !!:eek:
    oh PS,, Harley starts every time ..
     
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  14. use in conjunction with a test light. you can still get battery voltage with a bad connection. if the connection is good the light will illuminate.
     
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  15. if battery voltage is present but drops away when current is required. almost always a relay or dirty/burnt or corroded connection in the circuit
     
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  16. thank you ,,,for sure,, but this one is easy ,it is not a voltage / battery prob , it is a fuel pump non priming issue ( it is easy you can can hear it prime every time you turn the key on , cant hear it it dont start, hear it it starts everytime ) prob is i dont know why it sometines does not,, either relay , unlikely as replaced one year ago, or other feed or pump itsself,,, hope it does not return .
     
  17. never say never. firstly. check for power (with test light) you can make one in 5mins. dont disconnect fuel pump or disturb plug to much if possible. check for voltage. on pump side and loom side. got got the latter but not the former?
    you have just diagnosed it.
    work your way back. or bridge out the two main pins on yer pump rely. working reliably?
    you have just diagnosed it. think of electrics as pluming to stop you getting confused.
    voltage=pressure
    current=flow
    resistance=tap. like most things its only as complicated as you make it.
     
  18. true story. my nephews car (good mechanic, pish electrician) was of the road for six months due to a non spark fault. tried what he thought was everything including renewing the timing chain kit, he eventually got it up to me, battery voltage at coils when disconnected nothing when connected. disconnect the injectors voltage at coils increased to 6 or 7v. had to be a poor connection. checked all accessible wiring (look for little white blistering on wire insulation, it can often mean there is a corroded or broken wire inside) checked fuse with a multi meter for continuity seemed fine. but i dropped it trying to refit it. fitted a new one. sorted..?.
    i dug out the old one and put a current through it. it went open circuit. took current away continuity returned. there was a hairline crack in it which broke down under load. ie, you would get pressure but no flow. if you think about it, kinda like standing on a garden hose.
     
  19. 2 easy. Has an alarm ever been fitted to your bike?
    If it has, one of the ways the alarm functions is to interrupt the supply to the fuel pump. There is a possibility that an alarm has been fitted at one time, then removed by the owner as they are a p.i.a.
    It's possible that when the alarm was removed, the wiring to the pump which was 'intercepted' to allow the alarm's wiring to effectively break the circuit has not been properly reconnected. Eg- the wires were just twisted back together and not soldered to make an effective joint, or possibly they were badly soldered back together and have now broken down so they only intermittently provide full flow of power.

    If it was me, the first thing I would do would be to fit a brand new relay ( just to eliminate the possibility of the one you recently fitted being u/s).
    If still experiencing intermittent starting problems and you are not competent fault finding to find high resistance or open circuit in the supply to pump, fit a temporary +12v supply directly to the pump and see if that cures the issue.

    When was the fuel filter last changed?
     
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