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  • Carb questions (and some pictures)

    I disassembled my XJ carbs for a thorough cleaning, soaking the rack in Pine-sol for a day and a half and cleaning everything else with carb cleaner. I have a few questions I'm looking for some help with, snapped some pics for clarification.

    Should I replace this float? The edge of it right by the fuel T is a little ragged and separating from the metal.

    [IMG][/IMG]

    On to the float height, I'm not clear on the process even though I read some posts about it. Plastic floats are set at 23mm which = .905 inches. I turned the carbs upside down and put the new gaskets on. Then I set my dial calipers at .905 and checked them like this:

    [IMG][/IMG]

    My FSM describes a way different process, jacking up the bike and shimming the center stand to insure the carb bank is level and plumb, let the bike run a few minutes to obtain correct fuel level, and then check the level of each carb with a clear piece of fuel line connected to the bowl drain. The correct level is 3mm +/- 1mm below the "carburetor Mixing chamber body edge."
    Are the 2 methods comparable? Which method to use?

    The tech tip for Carb Cleaning 101 says to replace the rubber O-rings on the idle mixture screws if they are over 1 yr old. I can't find a part number anywhere for the idle mixture screw ass'y (because the carbs come factory with a plug in the tower?) so where do you buy these?

    And finally, the starter jet/choke shaft won't move. It worked fine after I pulled the carbs out of the Pine-sol but I noticed tonight that it's stuck part way open (here's a couple pics). Any idea why?

    [IMG][/IMG]

    [IMG][/IMG]

    Sorry this is so long, thanks in advance for any help you can give me.
    Billy

    1982 XJ1100, Ceramic Coated Headers, Raptor ACCT, Barnett Clutch Springs, Dremmel Fix, TC's Fuse Block, De-Linked S/S Brake Lines, 850 Final Drive, Yahman's YICS Eliminator, Pods, stock jets

  • #2
    As to the float, if it is coming apart, you may want to replace it. Typically the plastic ones are good for a lifetime though.

    As to measuring the float height, first, you measure the height from the gasket flange but with the gasket removed. So remove the gasket, then measure from that surface to the highest part of the float like you were measuring.

    As to the other method. On the 81 XS and the XJ models, they changed the float bowl to have a nipple to put a hose on, and still access the screw to open and close the drain. On those models it is recommended to put a hose to each carb drain, with the bike level side to side, and find the level of fuel in the float bowl. Adjust the float heights in each carb till the level is correct on each.

    My personal approach is that measuring the float from the gasket surface is close enough, just my opinion, others will disagree.
    Life is what happens while your planning everything else!

    When your work speaks for itself, don't interrupt.

    81 XS1100 Special - Humpty Dumpty
    80 XS1100 Special - Project Resurrection


    Previously owned
    93 GSX600F
    80 XS1100 Special - Ruby
    81 XS1100 Special
    81 CB750 C
    80 CB750 C
    78 XS750

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    • #3
      Also, you need to measure each side of the float on each carb. So, it is actually 8 measuents, make sure both sides are the same. You can twist the float to adjust it.

      As to the choke, in the pics it looks closed so you would need to pull out to open it.
      Nathan
      KD9ARL

      μολὼν λαβέ

      1978 XS1100E
      K&N Filter
      #45 pilot Jet, #137.5 Main Jet
      OEM Exhaust
      ATK Fork Brace
      LED Dash lights
      Ammeter, Oil Pressure, Oil Temp, and Volt Meters

      Green Monster Coils
      SS Brake Lines
      Vision 550 Auto Tensioner

      In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

      Theodore Roosevelt

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      • #4
        After soaking/sonic bathing carbs you can lose lubricant from around any of the moving parts, it happens regularly. Straight after removing from sonic bath I spray the carbs with WD40 to drive out any moisture and relube moving parts then use light oil, the choke mechanism rods and plungers are extremely prone to this.
        Tom
        1982 5K7 Sport, restored to original from a wreck
        1978 2H9 (E), my original XS11, mostly original
        1980 2H9 monoshocked (avatar pic)http://i145.photobucket.com/albums/r...psf30aa1c8.jpg
        1982 XJ1100, waiting resto to original

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        • #5
          Setting floats at the static level(23mm) will be real close to the 3mm down spcified. Leveling bike, which includes for and aft(block of wood under front wheel to level), bike already previously warmed up, this works good to check that ALL fuel levels are the same. This is to be done with bike running, so wanna be careful and try not to allow fuel to hit the exhaust.
          81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top.

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          • #6
            Thanks for the clarification on checking float height. I'm going to replace the float that is coming apart. And WD-40 freed up the choke rod, moves freely now, appreciate the info.

            Has anybody out there replaced the idle mixture screw assemblies, if so where did you order them from?
            Billy

            1982 XJ1100, Ceramic Coated Headers, Raptor ACCT, Barnett Clutch Springs, Dremmel Fix, TC's Fuse Block, De-Linked S/S Brake Lines, 850 Final Drive, Yahman's YICS Eliminator, Pods, stock jets

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            • #7
              Originally posted by BillyRok View Post
              Thanks for the clarification on checking float height. I'm going to replace the float that is coming apart. And WD-40 freed up the choke rod, moves freely now, appreciate the info.

              Has anybody out there replaced the idle mixture screw assemblies, if so where did you order them from?
              Several sources for the idle mix....some good....some not so.... If you remove idle mix screws, your likely gonna need the teeny-teeny o-rings for all four and possibly the teeny-teeny washers that o-rings ride on. Over years those tiny o-rings get hard and break into tiny pieces once you disturb those idle mix screws. NA for either from mother Yammy, but your in luck as they are still avaiable from Suzuki. O-ring part#:13295-29900 Washer#:13291-29900. If replacing idle mix screws(which they are not usually an issue on the later carbs), any source will work and don't have to be actual Genuine Mikuni like the pilot, main, and air jets have to be. K&L and RD are copies of Mikuni, but unfortunately not sized equivelant to Mikunis even tho they be stamped the same size. Jetting HAS to be Genuine Mikuni with these carbs or you'll chase your tail trying to tune out any glitches.
              81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top.

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