86 VF500F - Carbs and Docs

Discussion in 'Mechanics Garage' started by Ghostybits, Jan 25, 2018.

  1. Ghostybits

    Ghostybits New Member

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    Hey Guys,

    I'm Ghosty, nice to meet ya.
    First time posting to the forum, been lurking for a few weeks now.

    I grabbed a 1986 VF500F from a police auction for a grand, my first street bike, and I am absolutely loving it.

    So I put about 850~ miles on the clock since I picked her up, but I was noticing some odd behavior on freeways she would love it for about 10 or so minutes, and then I would start to feel a loss of power and I would have to be at WOT just to keep her at 75 and when I would pull off, if I pulled in the clutch and let the revs dip down to idle the bike would die.

    This would not happen at all, on surface streets, but the second I would take the bike on the freeway, it was kaput. Ended up checking the headers and found out that the 4th cylinder was not firing.

    Loosened up the drain screws and low and behold, the 4th carb was bone dry.

    It's odd though because the bike would run perfectly for hours on surface streets, and she would start right up cold.

    We ended up ripping the carbs off the bike to see if anything was messed up, but the carbs are in great condition, bowls were super clean, none of the jets were blocked, all the slides had good vaccum, couldn't see any real wear on the float valve.

    So we put everything back together and lo and behold now we cant get the bike to start without a nice fat dose of starter fluid.

    We have good spark, and good compression so I am positive it is the carbs, but I can't understand why the 4th carb isn't getting fuel.

    I ordered some new float valves, and a float level gauge. in the hopes that maybe I can get my baby started again.

    But for now I am relegated to being a filthy cager.

    TL; DR I pretend to know what I am talking about, bike used to run strong on surface streets, died on freeways, took off carbs now bike wont start.

    Any chance someone knows the float level for the 86 carbs? I have the Clymer manual, but it doesn't have the 86' on there

    Also any thoughts on my situation as a whole? I just want to get her running again so I can take her back through the twisties.
     
    Last edited: Jan 25, 2018
  2. Mind_Surfer

    Mind_Surfer New Member

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    Contaminated fuel system. Fuel tank, you wanna check that. Carburetors, need cleaning real good (ask me how I know). Send them off if necessary


    Ethanol free 93 octane if available.

    Your manual does not have any 1986 addendum? Clarify please.

    I have same model of motorcycle, original owner. Rode it out a few days ago. Fantastic motorcycle, very sharp looking too.

    Do as much maintenance as you can: valve clearances. Carburetor synchronization. brake and clutch fluid, flush it all. Coolant too. Fork oil too. Caliper bolts and pins, you may need to do a run-up on them too.

    Congratulations and best wishes.

    Sent from my XT1031 using Tapatalk
     
    Last edited: Jan 25, 2018
  3. squirrelman

    squirrelman Member

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    anytime you acquire a new old bike it's best to drain and FLUSH the fuel tank, first thing so crap doesn't get into carbs.

    seems like you need to check the small fuel filters just above the float needle seats and also for free fuel flow through the petcock.

    rarely but sometimes you might find a float needle stuck to its seat, in which case no fuel getting into that carb.
     
  4. Ghostybits

    Ghostybits New Member

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    I'm getting free fuel flow through the petcock

    I really am hoping that these new float valves fix it. For 1000 bones it is in good condition
     
  5. Mind_Surfer

    Mind_Surfer New Member

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    Probably gonna need more than just simple seat & needle swap. Thorough cleaning, remember that.

    Sent from my XT1031 using Tapatalk
     
  6. Ghostybits

    Ghostybits New Member

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    We pulled the carbs back off and replaced the float valve and...

    The bike now starts without starter fluid!
    Woot! But she is idling pretty rough.
    We only replaced the one on the #4 carb,
    gave that carb a good clean while we had it open. Gonna pull the other carbs open and give them a good clean tomorrow, and double check all the float levels and hopefully she'll accept throttle.

    Otherwise I did notice that the plugs for the pilot screws are missing. Gonna check that those are turned out to the factory spec.

    Maybe I'll finally put my 900th mile on the bike.
     
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