Carbs need to be synchronized

Discussion in 'Mechanics Garage' started by jorgescar69, Apr 6, 2021.

  1. jorgescar69

    jorgescar69 New Member

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    Hello...
    3 gen
    So I need to know what the order is for adjusting the carburetors synchronizing screws.
    1 in front
    2 in the rear.
    I just cant get them to sync!
     
  2. Diving Pete

    Diving Pete Insider

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    ok so to synch your carbs, you balance the front pair together, the rear pair together, then both pairs to each other. Where are you struggling ?
     
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  3. jorgescar69

    jorgescar69 New Member

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    Which one of the two rear screws is first?
    L or R?
     
  4. ridervfr

    ridervfr Member

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    Hey doode! Glad your viffer is running still, I mean they are indestructible unless you run them out of oil or something. Thing with these carburetors, and I hate to say it, you have to start with a good bench synchronization. That being said, pull the cables, and carbs. Get them on your bench, and turn the screws you mentioned while you look at the throttle plates in relation to the small holes (don't ask what they do, I think its low speed circuit) idea here is to play "Peak-ah'Boo" with the holes in relation to the throttle plates, take your time and snap the throttle every so often to keep it all honest. Eventually, your gona have a CH of a hole visiable on all four of the throttle blades, at that point, re-install and warm up bike. I have four of the brass nipples (originally bike only had two, install 4 caps on them and when ever you want to do the synchronization its a breeze) install you manometer or what ever balance tool you got and get the bike as high as you can, (air table) and get about three or four flash lights out, and your trusty 90 degree screwdriver and if you did your bench synch correctly, you should barely have to touch the adjusters. If you have the manual, it tells you which adjuster does what, I just touch them lightly and look at the carb balancing tool I am using. I have to say the most important part of the job is having a good right angle screwdriver, if you dont have that your fuckity fucked. :mech:
     

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  5. squirrelman

    squirrelman Member

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    once the bench synch is done and gauges are set up, don't turn any screw more than about 1/16 of a turn or things could go bad quickly.
     
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  6. ridervfr

    ridervfr Member

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    Hence a CH - a curly one possibly
     
  7. jorgescar69

    jorgescar69 New Member

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    Yeah... I backed out the 2 4 till it fell out.
    Carbs are off and getting into the sync
     
  8. squirrelman

    squirrelman Member

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    remember, the SEQUENCE of working on the screws is all-important.
     
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  9. jorgescar69

    jorgescar69 New Member

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    I found my problem!
    Looks like I'm back to ebay.
    Boot for #1 is torn!
     

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  10. jorgescar69

    jorgescar69 New Member

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    So I used a strip of paper for the bench sync.
    But I just ordered the replacement boots new from Ebay.
    It's like the summer of 2014 all over again.
    I new something was wrong with 33 mph!
    I left a set of boots back in Westfield, NY.
     
  11. ridervfr

    ridervfr Member

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    Lots of ways to skin a cat, paper, feeler gauge, drill bits, I use my eye balls and a reference point with a hoe (hole) trying to be funny. When I get all the hoes, set with the bench synch while snapping the throttle every so often, I use the idle adjustment screw to make sure they are all behaving together. At that point I re-install them and do the deal we were talking about.

    Intake Boots, or insulator bands as they like to call them are critical! If you have an intake leak your gona be fuckity fucked. Flip side is when they are nice and new, it makes removing the carburetors a breeze.

    While your in there, you should change your thermastat along with associated 0-ring. Make sure you situate the hole in the t-stat towards the front (its all in the manual-you do have the manual? right?) Peace
     
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  12. jorgescar69

    jorgescar69 New Member

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    Yes...
    I have the books!
    Just didn't expect the cylinder 1 boot to be split open like it was. It felt like a vacuum leak. It just would not get synchronized.
    Email said it was just shipped.
     
  13. squirrelman

    squirrelman Member

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    drill bits are the least accurate way to synch, not recommended.
     
  14. squirrelman

    squirrelman Member

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    when synch is good your bike can idle smoothly down to about 800 rpm.
     
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  15. ridervfr

    ridervfr Member

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    Yep, comes into play when your in your neighborhood and you don't wana run anyone over, 1st gear with the engine idling along. Its a CH, everything comes back to it yah know! The CH :loco:
     
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  16. jorgescar69

    jorgescar69 New Member

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    I'm in duh hood... yo!
    Faster you down the road, the safer you are.
    But knowing why it lost idle at the light is worth the wait for new rubber.
     
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