Help, I'm flummoxed, Hard starting VF700

Discussion in '1st & 2nd Generation 1983-1989' started by steves, Dec 26, 2007.

  1. steves

    steves New Member

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    I own three first gen Interceptors, 83,84, and 85. I've resurrected them all from junk but the 84 VF700 is giving me fits. When being started cold it appears to want to fire on one cylinder. It will only idle (just barely) with the throttle closed. Open the throttle and it dies. After about a minute or more another cylinder seems to light up. At that point I can give it some throttle and after some throttle blipping I can get the other two cylinders to fire and it will quickly clean up and run on all four. Then everything is fine until I try to restart it cold and the process starts all over.
    The bike has a replacement Ebay engine that I bought after finding out that objectionable engine noises could not be cured with a valve adjustment. This starting problem preceeded the engine swap and has persisted unchanged until now. Since installing the newer, better sounding, engine I have done the following, in this order to track down the problem:

    -swapped carbs for a California VF700 set. Cleaned these carbs, which
    were really plugged. I didn't do anything to the capped pilot screws.
    -swapped out the fuel pump from a running bike, no change.
    -swapped out the spark boxes from a running bike, no change.
    -swapped out the fuel pump from a running bike, no change.
    -swapped out the coils and wires from a running bike, no change.

    At this point I am really starting to suspect plugged pilot jet circuits. I know that the main jets and slow jets were completly plugged. Has anybody ever heard of the pilot air screw jets being plugged even though they have not been uncapped since leaving the factory? Is there anything else I might have missed?
     
  2. masonv45

    masonv45 New Member

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    Unless you have soaked and blown out with compressed air, you have not done a proper carb cleaning. Remove the caps and pilot jet, spring, washer, and o-ring (now probably hard as a rock or swelled up from the carb cleaner hitting it)

    If the main and slow jets were plugged, then more than likely the pilot jets are plugged too. That's why you are having a tough time getting the bike to run.

    See tutorial with good pictures here: http://users.rcn.com/kochc/moto/carb/carb.html
    P.S. if you go with the soak procedure, give me a holler and I'll give you some tips.
     
  3. steves

    steves New Member

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    Hard starting VF700

    Thanks for the advice. I suspected that it was a fuel related problem. I drilled out the pilot screw caps, determined their setting, pulled them out and blew out chambers with carb cleaner and compressed air, and replaced them to their prior settings. Then I took the bike for a test drive. It seemed to run fine, but I still needed to determine how it would restart in the morning. Start up the next morning was still difficult, but better. I checked and found that my other 2 Interceptors rev up to around 3000 rpm when the choke is applied, but this one was hardly affected by full choke application. That made me suspect the starter circuit so I decided to pull the carbs one more time and clean out the starter jets. Although they didn't appear to be plugged the linkage wasn't allowing the back two carbs to open fully with the choke lever. With a little cleaning and linkage bending I got them all to open properly and retract when the lever was returned to the off position. Since the carbs were off I bench synched the throttle plates. Now morning start ups seem to be much better. I am wondering if start ups would improve if I opened up the pilot screws a half turn each to enrichen the idle mixture. Would this have an effect on my gas mileage? Any recommendations from here?
     
  4. squirrelman

    squirrelman Member

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    easily worth trying...mostly affects fuel mix when at idle and just slightly above, so not much loss of MPG.

    Have you tried the Sea Foam treatment?? might well help your situation.
     
  5. steves

    steves New Member

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    Hard starting VF700

    What's the sea foam treatment and where do you get the stuff?
     
  6. masonv45

    masonv45 New Member

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    You can get sea-foam at most auto-parts shops. It reduces carbon and gas varnish. Typical treatment is to use 1/2 to an entire can of the "motor treatment" in one tank. (Don't use the "Deep Creep" for this treatment)

    Lots of info here: http://www.seafoamsales.com/products.htm
     
  7. squirrelman

    squirrelman Member

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    True, Sea Foam might not be the miracle-cure snake oil treatment of the century.....but most people who try it see results!!
    IT's primary use is to clean out the smaller passages in carb jets.

    It couldn't hoit..........unless it gets on your paint!
    And post up if you think it helped??
     
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