85 VF500F Annoyance

Discussion in '1st & 2nd Generation 1983-1989' started by bigmac9137, Jul 9, 2010.

  1. bigmac9137

    bigmac9137 New Member

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    does not start well or at all when engine is hot, usually starts right away when its cold. If i turn off the engine when hot and try to start it again I have to wait like 15 minutes for the engine to cool. It does everything but actually fire and turn over. any ideas? already tried creating a gravity feed with fuel pump but didnt work, i honestly think spark plugs
     
    bigmac9137, Jul 9, 2010


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  2. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    Have you pulled a plug and checked for spark when it's hot?

    When everything's cold, break your plugs loose to make sure they aren't siezed up in the head. Who knows how long they've been in there and trying to remove them for the 1st time in years with the head hot can pull the threads out with it.

    Look at the plugs and check for proper gap. Re gap or replace if necessary (i.e. fouled out and carbon). Snug the plugs back up and run the bike. When it's hot and won't start, burn the shit out of your fingers by removing one of the plugs, connecting the plug wire and grounding the plug against the head. Turn the motor over and look for good blue spark.

    You may consider trying a plug on the front and a plug on the rear of the motor since they are independent systems. Also, have you tried holding the throttle wide open while cranking hot? If the engine is flooding out, holding the throttle open might clear it out and get it to fire.
     
    tinkerinWstuff, Jul 9, 2010


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  3. bigmac9137

    bigmac9137 New Member

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    I tried to change the spark plugs with a 5/8" hex but for some reason it was JUST too small for the hex, so im thinking some wierd metric spark plug? 18mm? I tried for an hour, no luck. I have not tried to hold the throttle wide open, i will though. Ill get back to you later about it. thanks
     
    bigmac9137, Jul 9, 2010


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  4. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    don't crank the thing so long you burn up your starter. no more than about 10 sec at a time with 10 second break or so between IMO.
     
    tinkerinWstuff, Jul 9, 2010


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  5. crustyrider

    crustyrider New Member

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    check you coils.....one could be bad.....feel them..if one is WAY hot... you have a bad coil.,, also check all your connections...you may have a loose one,, OR you could have a fuel pump over heating....
     
    crustyrider, Jul 9, 2010


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  6. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    He already tried eliminating the fuel pump in favor of gravity feed to eliminate that possibility.

    Best to start simple in my opinion. figure out if we're dealing with a sparks issue or fuel issue. Best to figure which tree is the right one to be barking up before running around to each one. Since the guy isn't aware of how to try and start a flooded motor, I doubt he'll know the difference between a normal coil and a hot one.
     
    tinkerinWstuff, Jul 9, 2010


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  7. bigmac9137

    bigmac9137 New Member

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    Alright, i mean im not the biggest gearhead but I got a manual in the mail, and I have lots of people around me who know motors pretty well so i can figure it out, haha. My plan is to start cheap and work up, spark plugs first, just gotta try the metric socket instead, who knows if they are frozen yet. Ill check coils then too. hopefully its spark plugs though, easy, cheap fix. And yes, the gravity did not do anything and my fuel pump is not overheating, already checked that.
     
    bigmac9137, Jul 9, 2010


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  8. slowbird

    slowbird Member

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    Wish I could help with the Spark Plugs.

    When I did mine I was having issue removing them also....then I used the Spark Plug tool in the bikes toolkit and that worked great.
     
    slowbird, Jul 9, 2010


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  9. bigmac9137

    bigmac9137 New Member

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    the spark plugs were 18mm....AND it fixed my starting problem! shes a gem now, watch out! woot woot
     
    bigmac9137, Jul 23, 2010


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  10. GreyVF750F

    GreyVF750F Member

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    Could be the pilot screw setting. Take the easiest one and turn all the way in counting the turns. Seat it gently. If it's over 2 1/2 turns, then it may be to rich when trying to start hot. If that's the case do the pilot screw adjustment. Also make sure your carbs are venting properly.
     
    GreyVF750F, Jul 23, 2010


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