86 VFR750 Stalling

Discussion in 'Mechanics Garage' started by VFR182, Mar 12, 2009.

  1. VFR182

    VFR182 New Member

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    Ok the bike has been running fine for months then after full throttle runs it would stall. This would happen once in a while. Then a few weeks later I started noticing a slight loss of power and when it would stall it would take a few minutes before it would start again. I thought it was the fuel pump because it wouldnt always make the click sound when the ignition would be turned on. A friend brought over the fuel pmp off their 87 vfr and I installed it and fired up the bike. It ran great, and the power was back. Ran it that day for a while then on the way back it stalled again and didnt start for a few minutes, then after it started it stalled about 1 min after, took a while to start again, then finally pulled up to house. I dont think the pmp from my friends bike was bad, I mean its possible, but Im still lost and dont know what to do. What confuses me is that loss of power with old pump, then with new pump power is back but still stalls? See what Im saying? Its like the old pump was bad because powers back, but yet its still stalling???? Please any ideas? Thanks
     
  2. VFR182

    VFR182 New Member

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    oh and btw I just changed the plugs, check the fuel filtr and re charged the k&n
     
  3. Maggot

    Maggot New Member

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    Make sure your fuel tank is getting air, check the breather line and make sure it's clear!
     
  4. TOE CUTTER

    TOE CUTTER Mullet Man

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    fuel

    You may want to check the relay for the fuel pump . I have had that give me problems in the past. You can bypass the relay and see if the problem goes away.
     
  5. crustyrider

    crustyrider New Member

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    you could try gravity feed just to see if its starving for fuel. when was the last time you cleaned the carbs? check your coils to see if they are getting way hot. Not sit dies when it heats way up then the car will run after it cools down.if its bad ure how that works. but with a car that runs a coil
     
  6. squirrelman

    squirrelman Member

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    IF you can rule out the fuel pump as the cause , then your next logical check is electrics, namely the connetions to/from the R/R, and the pick-up coils.
     
    Last edited: Mar 17, 2009
  7. VFR182

    VFR182 New Member

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    Ok guys I left work so I could work on the bike. To answer some questions the were cleaned a few months ago. I checked the relay and the current seems fine, although it was done while the bike was ideling for a few minutes. I will now check the breather line, and the R/R conections.
     
  8. VFR182

    VFR182 New Member

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    :confused:Ok breathr is free, conections to coils and R/R are ok and they are getting power. Im still lost ????
     
  9. squirrelman

    squirrelman Member

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    CHECK the "pick-up" coils as well as the ignition coils.

    I had a simillar problem a few years ago: the bike woluld run fine untill it got to operating temperature, and then would stall with no sparks. I tested the pick-up coils as per factory service manual and found the problem there.
     
  10. VFR182

    VFR182 New Member

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    Ok going to check that.
    BTW could this have anything to do with it?
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  11. crustyrider

    crustyrider New Member

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    I don't know but I would change it if I was you.......thats your main fuse should be 30 amp and it looks like thats what you got in it...
     
  12. VFR182

    VFR182 New Member

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    On it. Im wondering what caused it to do that
     
  13. dizzy

    dizzy New Member

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    I don't know if it's THE problem but it's a potential future problem. If you lost contact on those thick wires you would either lose all your bike's electrical power like the fuse blew, or your charging system would quit working. Is that's what's happening? Didn't sound like it from your post...but you should fix this and retest. You should also locate and inspect the couplers for the reg/rec and the stator.

    You need to eliminate your spark as being the problem. Buy one more spark (save the time of threading one out roadside), go out for a ride, when it dies...pull the resistor caps and immediately check spark...at least one front and one rear. Try to do a couple tests.

    BTW...these can be a little tricky troubleshooting because...If the wrong ignition subsystem fails (either front or back) you lose your fuel cut relay signal and it looks and feels an awful lot like the bike's running out of fuel when actually it's losing spark on two cyinders...and then running out of gas because of the ignition problem. I know for a fact alot of people have purchased fuel cut relays and fuel pumps when the whole time the problem was ignition.

    To answer your question on the cause of those overheated wires...riding when the battery is extremely discharged or weak...poor connection at or somewhere in the starter relay...bad reg/rec...I'd say they would be most common.
     
    Last edited: Mar 15, 2009
  14. VFR182

    VFR182 New Member

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    Ok I will try but seems kinda hard as I cant reach them with out taking off the radiator and tank:frown:
     
  15. dizzy

    dizzy New Member

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    It is hard...welcome to my world. It's the simplist way to know for sure. I was thinkin' if you removed the side cowls before you ride you could at least access the resistor caps.
     
  16. VFR182

    VFR182 New Member

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    Yeah indeed! Ok the fairings were already off the bike, and even with those plastics off I still cant reach, so what Im doing is taking off the rear seat cover and taking off the main bolt for the gas tank. So I can just unlock the seat and raise the tank all fast so I cant get to the rear caps. As for the front I will leave the top left radiator bolt off " it will still be very secure and I will also have a zip tie on for extra strength ad so i cant just break it off fast" so I can just move it a tad to reach the front cap. The good thing is the bike usually doesnt start for at least five minutes, so at least the window of time isnt too small.
     
  17. dizzy

    dizzy New Member

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    Sounds great...good thinkin'
     
  18. squirrelman

    squirrelman Member

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    I had at least 2 '86 VFRs that melted down in the same horrible manner and saw same on a '97 too.
     
  19. dizzy

    dizzy New Member

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    And I agree the pick-up...or pulse generators you mentioned earlier in the post are high on the list of culprits. Over the years, I've seen many fail in this way on more common Honda models...get hot and quit working.

    Matter of fact VFR182...it wouldn't be a bad idea to locate the pulse generator connector and ohm them out...figure out how to test...while they're working, and add them to your list of things to check when your bike fails next time.

    In years past, when I commonly worked on GL1200 Wings...if I got one for repair with the same symptoms as your viffer, I would automatically replace the pulse gens. I could easily spend that much of the customers money just getting the stupid bike to fail. As much as I hate to replace parts without actually confirming they're faulty, in that case because of the relative low cost of parts and labor it was a wise move as virtually everytime it WAS the problem.
     
  20. VFR182

    VFR182 New Member

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    Oh wow what a time this has been to check this issue. BTW I just remembered something. When I ride the bike very mellow, it runs for a very long time. Then when I ride it hard for a while that when it stalls. So I was riding around normal like, and then I remembered how it gets when I go full throttle. The thing is I dont ride hard on normal streets, if any its out on the lone highways in the country or desert and I really didnt want the bike to stall there again. Anyways I headed out that way and since there have been some bike races off in that area this past few days, there were hidden sherriffs cars etc all over so I really couldnt do much. I will try again in a little while. BTW I noticed that when I start to keep the rpms high and also when I was full throttle, before it would stall some wires or wire in the harness behind the rt cover really heat up. Anyone know where I can buy some new pickup coils online?
     
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