One rich carb on my airhead

Discussion in 'Airheads' started by Craig in Alabama, Nov 18, 2010.

  1. rufusswan

    rufusswan Been here awhile

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    If you can, blow water or something thru the passages then you can see they are flowing and which one comes out where. I think there are two that open in the carb throat.
    #21
  2. fishkens

    fishkens Long timer

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    I use a can of carb cleaner and a red straw to blow through passage ways.
    #22
  3. Craig in Alabama

    Craig in Alabama Adventurer

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    Hi Folks,
    I figured out which air passage fed the idle jet and verified that it was clear. But I noticed that the space the jet screws into wasn't nice and symetrical like the main jet area. It looks a bit irregular. I also noticed that when I screwed the jet in or out there wasn't much resistance from the o-ring like there should be. Hmmm...
    Turns out that gas was apparently getting sucked up around the idle jet instead of just into the jet hole. I had a pack of o-rings that are designed to be used in fuel, so I got a slightly fatter one and doubled them up. Nice and tight when I screwed the jet in. Cautiously optimistic, I set the carb up like it should be (air screw 1.25 turns out) and put it all back together. I knew it was going to be right when I had to use the choke to start it up. Then it went into a nice steady idle with the air screws where they are supposed to be.
    I took it for a warm-up ride and everything feels just like it should. Transition off idle is much smoother. I balanced the carbs when I got home and it was much easier than it has been before. I'm going to take it for a ride in a few minutes and verify that everything is right. Hopefully my mileage will be a lot better.
    So I don't know if I put the wrong o-ring on there when I originally cleaned out the carbs or if the idle jet orifice is buggered up, but it seems to be fixed. I really appreciate everyone's input.
    I'll report back after the ride.
    Cheers!
    Craig
    #23
  4. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Good. You're making progress one little chip at at time. :D
    #24
  5. AustinJake

    AustinJake DR650 - Versys

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    If the right side carb has ever been blocked and clogged and if a PO has ever used a piece of wire or a small drill bit to clean the main jet, this will be the problem, I know, it's happened to me on a carb before, I chased the rich condition through every avenue till I got a new main jet and eye-balled the 2 jets side by side, the "used" one was significantly bigger. Put the new, correct-size jet in, problem solved instantly.
    #25
  6. fishkens

    fishkens Long timer

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    :clap:clap:clap


    I'm curious about the irregularity of the carb body. Is it oval as if it was clamped in a vise? The threads buggered? Not a big deal, just curious.
    #26
  7. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Soft brass threading into softer pot metal. Get heavy-handed and anything can happen. :cry
    #27
  8. Two Wheel Moto

    Two Wheel Moto Dodgin' cages

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    I skimmed through the posts and I hope I am not repeating this. But is it possible that the enrichener is in backwards? I was having trouble with cold starts when I got my airhead. And when it was warm one cylinder was way rich with black soot on the plug. I was reading that the enrichener is easy to put in backwards. I tore into the carb and sure enough mine was backwards. I turned it around and it starts no matter how cold and runs like a champ.
    #28
  9. Craig in Alabama

    Craig in Alabama Adventurer

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    Madison, AL
    I just got back from a test ride. The bike ran great! I left with a full tank and put 95 miles on of mostly back roads at 60 - 70 mph. I used 2.25 gallons of fuel which puts my mileage at about 42mpg! And did I mention the bike ran great?

    Granted I probably need to do some fine tuning to the carbsync, but this is certainly something I can live with. I balanced the carbs to be smoothest at about 3k rpm. Idle was fine and I think everything is hunky dory. I haven't pulled a plug yet, but I'm sure it will look better than yesterday (same route - 30mpg).

    The opening where the idle jet goes looks like someone either screwed the wrong thing in there or cleaned it out with a screwdriver. I don't know. The other openings are nice smooth bores with nice clean threads. This just looks messed up, but the jet screws in just fine and the threads don't appear to be messed up. Next time I have to take the carbs off (which I hope is a while), I'll compare. But for now, I'm going to leave it alone.

    Maybe I used the wrong o-ring initially, but I was very careful (I thought). In any case, all seems to be good for now.
    Thanks, everybody!
    Craig :D
    #29
  10. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    If that idle jet carb passage is damaged, Bing has a "carb doctor" who can reportedly work miracles on the damaged threads/jet seat/etc. If that looks like it will be a problem, you might want to give Bing a call and see if they can do anything with it.
    #30
  11. Craig in Alabama

    Craig in Alabama Adventurer

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    Madison, AL
    The idle jet area is definitely not right. It looks almost as if somebody may have dremeled out a little bit of it, possibly to get the jet out if it was stuck. I don't know. The second o-ring seems to be doing the trick. I wouldn't mind getting hold of a spare carb body just to have on hand. Thanks for the carb doctor info.

    It's another one of those things to keep in mind, like knowing that at my next oil change I need to be ready to re-thread one of the oil filter cover bolt holes. I know the shop that did all the work on the bike, and I really like them, but they had no business working on this bike. They did the carbs, an oil change and adjusted the valves. All three areas had something either mis-assembled or stripped out. With apologies to Forrest Gump, "Buying a used bike from someone you don't know is like a box of chocolates..."

    Cheers!
    Craig
    #31
  12. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    The important items on the idle jet drilling are the conical area where the tip of the jet seats and the bore where the o-ring fits. If the other areas are wonky they may not be a problem.
    #32