86 VFR750 Stalling

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

  1. VFR182

    VFR182 New Member

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    ok another thing haha. I checked spark before the ride and it was fine. I arched it with a screwdriver to the frame. So anyways the ppl at target think im crazy. I rode the bike for a while behind some buildings on an industrial road giving it hard throttle when I could, and it wouldnt stall. Haha I was actually pissed that it wouldnt stall :tongue: So anyways I pulled into the target and turned it off and tried to start it and it wouldnt start. Im yelling at myself cuz I cant get the gloves off and yelling at the seat for being stuck, and saying hurry man hurry man hurry aloud as ppl stared. Anyways I checked for spark as I was cranking the engine and nada, zip, 0 spark
     
  2. squirrelman

    squirrelman Member

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    OK, so now it's time to check the contacts in the "run-off" switch.......

    Also, check the connection between the ignition switch and wiring harness in front of the fusebox area (red plug).
     
  3. VFR182

    VFR182 New Member

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    Ok the contacs in the run off switch seem fine but one looks to be kinda darker. It still works fine. as for the plug from the ignition switch to harness, it seems fine besides being kind of sandy. "desert"
     
    Last edited: Mar 19, 2009
  4. VFR182

    VFR182 New Member

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    Still lost
     
  5. squirrelman

    squirrelman Member

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    OK, now time to check for blocked vent in fuel cap causing vaccum in tank as fuel is removed......
     
  6. VFR182

    VFR182 New Member

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    Cap is clear. Today we just let the bike idle with a shop fan in front, and after a while it stalled as usual. Just this time with no riding. That info prob doesnt make a difference but I was just saying.
     
  7. squirrelman

    squirrelman Member

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    Stalling after reaching operating temp sounds like pick-up coils (mentioned earlier).......or maybe black box computer.
     
  8. VFR182

    VFR182 New Member

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    Do you know where I could buy the pickups online??
     
  9. dizzy

    dizzy New Member

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    Might as well test 'em before you buy to make sure. It's pretty easy. You need an ohmeter...do you have one?

    They go from the engine to the 'black box' and there's a coupler in between. That is where you do your test so find that coupler. It'll be either a 3 or 4 pin with a blue/white, yellow white and either one or two green or green/white.

    Unplug it and take two tests (one for the front cylinder bank and one for the rear), you'll be testing the ENGINE side of the harness. Set your meter to ohms and go from the yellow/white to green (one reading), and then blue/white to green (second reading). Try it while your bike is working and you'll see around 400 - 500 ohms. Allow to fail and check again. If one or both readings are vastly different...by that I mean basically open circuit, the problem is the pulse generators (pick-ups). If it doesn't change much...the problem is elsewhere.
     
  10. masonv45

    masonv45 New Member

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    Are you running a filter "after" the fuel pump between it and the carbs?

    If so, the fuel filter could be causing the pump to stop running because the fuel filter causes "just enough" back pressure to stop the pump.

    This usually happens on full throttle applications as the fuel pump can't keep up with the demands of the carbs.
     
  11. VFR182

    VFR182 New Member

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    Ok guys back, sorry left town for work and just came back. Sometimes have to leave pretty damn fast. Anyways back to figuring whats up with this bike. I know I could drop it off at the shop but I like to do it muself if I can you know? So I will try to test with the ohmeter "hope it still works"

    Btw you think its just either the black box or the pickups? Im asking because i found a guy here selling those two items and I figured buy em anyways for replacement parts, but if you guys are pretty sure then I could just go ahead and put the new pickups on and run the bike then if its still doing it, install the new blackbox?
     
  12. 199q

    199q New Member

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    This is exatcly what my problem sounds like, except now the bike wont run sometimes, and runs great other times.


    do you have a multimeter? I would ohm out the pickups. they are easy to ohm if you have the FSM I believe they are supposed to be in the neighborhood of 450-650 ohms.

    There are two plugs on the right of the battery. i think its the one with 6 pins is the one you need to test?? I am at work right now and I cant really look at my FSM. anyone else know?
     
  13. dizzy

    dizzy New Member

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    It's best to confirm a failed part if you can get your bike to fail easily (gotta test while failed). You could just go right to the spark unit connector in the rear cowl, nearly everything ignition ends up there.

    Unplug the connector and test the harness side...
    PG that signals cylinders 1 and 3...yellow and white/yellow wires
    PG that signals cylinders 2 and 4...blue and white/blue

    Those should be 450 to 550 ohms...there's also a cam pulse generator on 86 models that is...white/black and yellow/black...that should be 400 to 500 ohms.
     
  14. VFR182

    VFR182 New Member

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    Thanks, Im on it. Oh btw that guy sold the parts, and all places say the PG are unavaliable since Honda discontinued the item. If thats the part that is needed where do I find it???????????? Thanks
     
  15. squirrelman

    squirrelman Member

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    SINCE Honda won't... your only choice is to find a reliable salvage yard to sell you the parts u need.
     
  16. VFR182

    VFR182 New Member

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    Ok so mu friend checked the PG and said there was a big drop in ohms. I found the part so I replaced it. Now when I tried to start it up, the solenoid just clicks when you hit the start button. "start-click" "start-click". engine not cranking. then I checked the connections etc and when i tried it again it did this insane rapid click. "start-clickclickclickclickclickclickclickclickclickclick" "start-clickclickclickclickclickclickclickclickclick". engine still not cranking. Tried it again 20 min later and and the engine started to crank very slowly as if the battery was low. So I figured it was drained so I charged it a bit and went over the connections again and now when I try it now it just does one click and the battery starts to sizzle until u let off the switch. Eh oh man so then for some reason i said maybe this new part has something to do with this. So there gos oil again, covers, gear, take off new part, put back old one blah blah only to see the same thing. I feel so stupid and this well, just sucks, im sooooooooooo lost
     
  17. 199q

    199q New Member

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    I have almost the same exact problem that you have:

    Just a quick BTW, my pickup tested good, however it is not passing voltage when the bike is trying to start, i need to pull a bunch of parts of to test some more. my mechanic/friend was saying it should be in the AC milivolts, and my fluke meter will measure down that low. but another test, not sure if it is it.

    I am in exactly your same boat. sounds like mine are failed as bad as yours are. my bike currently wont run. but every once and a while i will see spark.. then try again and bam nothing. I will let you know on my progress. I am going back at it on Tuesday after work.

    I got lucky, my next door neighbor is a certified Honda motorcycle mechanic, and is willing to work for some beer, and to help out a friend. a pretty cool dude!
     
  18. VFR182

    VFR182 New Member

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    Ok so mu friend checked the PG and said there was a big drop in ohms. I found the part so I replaced it. Now when I tried to start it up, the solenoid just clicks when you hit the start button. "start-click" "start-click". engine not cranking. then I checked the connections etc and when i tried it again it did this insane rapid click. "start-clickclickclickclickclickclickclickclickclickclick" "start-clickclickclickclickclickclickclickclickclick". engine still not cranking. Tried it again 20 min later and and the engine started to crank very slowly as if the battery was low. So I figured it was drained so I charged it a bit and went over the connections again and now when I try it now it just does one click and the battery starts to sizzle until u let off the switch.
     
  19. squirrelman

    squirrelman Member

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    you can test the starter motor itself using a jumper battery attached to the large wire on the starter and ground.....eliminating your bike's wiring and the bike battery entirely.

    All this action has drained your battery; don't even think of trying to start the bike if your battery doesn't show at least 12 volts, and 12.6 is really about right.

    do it spin??

    Pulse generators may test OK when cool but fail when hot.
     
  20. 199q

    199q New Member

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    sounds like you have a shorted wire somewhere in the starting circuit?
     
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