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Carbs are worse now

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  • Carbs are worse now

    So I cleaned the carbs.
    I had one very bad float needle. Unfoutunatly the kit I bought had
    different needles. I managed to get it to work (i think) I know the needle was sealing and the float height was good. The rest of the needles looked good so I just cleaned and reassembled. I put the carbs on the bike today and after some choke (and a battery recharge it was really cold this morning) It fired right up. It won't run too good without choke or a little throttle. I can tell from the exhaust it is running rich and after starting it without the air box I can see lots of vapor coming out of carb 1 (left most) and carb 3 (right middle) after shut down. Carb 1 has the different float needle. Carb 2's idle jet screw took only 1 1/8 turn to seat, all the rest were 2 turns so I set all the carbs to 2 turns. When I rev the engine I can see the slides stutter up (only firing on 2 or 3 cylinders?) the engine is very rough but no back fire or after fire.
    So do I need to start over do I still have float issues, another clog somewhere.


  • #2
    I just dissassembled the #1 float.
    I adjusted it a bit and am sure it works.

    Started the bike and same symptoms.
    Maby the plug is fouled now and I just not firing
    on all cylinders?


    • #3
      Another upate:
      I just noticed that the slide to this carb (the one pouring vapor) is different then the rest. This is the same carb that had the float needle crumble up on me. I noticed a few other things during the cleaning that lead me to think these carbs have been buggered up.
      I looks like carb 1 is not from this set.


      • #4
        Here's my suggestion: get another set of carbs off eBay or from SpecialK and start a-fresh. I have a suspicion that there's more fouled inside the carb than just build-up based on your statements (like some mangled parts in the float pivot).

        If you don't want to go that route (I always recommend working on a spare set of carbs -- so much easier to swap and it means a source of spare parts), tear down all the carbs, replace the parts that the jet kit has in it, and triple check the o-rings at the idle set screws. It sounds to me like a combination of things is happening:
        (A) Bad O-rings for the idle set screws;
        (B) Someone may have previously overtightened the screws for the idle circuit and may have ruined one or two of them (cylinders 1 & 3);
        (C) way out of sync.

        Once that's done, set the adjustments to 2 1/3 turns out, replace the plugs and retest & sync.

        Q: Which jetkit are you using (Ivan's, FactoryPro, K&N, DynoJet)?

        KNOW THIS: Carbs are not my strongest suite, and there are other people around here I defer to on carbs

        =-= The CyberPoet
        Remember The CyberPoet


        • #5
          Sounds like someone slapped together a set of carbs...............

          Look at the side of each carb and look for these numbers:


          These carbs should all be BST36SS Mikuni's..............which means 36mm openings at the engien side. Measure them!

          Jets should be 110 unless you've got a jet kit and then its if you have stock airfilter and/or aftermarket exhuast system.............

          Turns out on Air/Fuel mix screws: I'd say all of them at 2 should be fine.

          Floats set at 14.6mm.

          PM or e-mail me if I can help further............

          Although I don't have any 36mm carbs here, I have lots of the parts yo umay need.............
          I've owned over 70 Katanas - you think I know anything about them?
          Is there such a thing as TOO MANY BIKES?
          Can you go TOO FAST on a bike?
          Welcome to! Click here to register


          • #6
            OK, First off thanks for the replies.
            Second I guess I should have kept my bidding open on the carb set on ebay.
            Third, I bought carb re-build kits from oldbikebarn.
            I bought the kit for the GS 550 because I found it uses the BST36ss but only the bowl gasket and some of the o-rings were right. I think the #1 idle jet o-ring may be missing.
            I could'nt see it but didn't want to ruin it digging around for it. The float seems fine.
            Without the idle jet o-ring I'm just dumping fuel into that carb right?
            Special K, how about the float needle for this carb.
            (the difference between the one I used, from the kit,and the old one is the plunger is longer and seems to have a firmer spring. )
            This float needle is the square one with the cone seal. Also would you have the idle jet o-rings?


            • #7
              I still can't find any reference to idel another name for it?

              On those float needles............All the ones I've seem on the Kats are sorta sqaure and have a round tapered rubber tip. I always look closely at teh rubber tip, usually under a magnifying glass, and make sure they don't have a groove worn in them. If they do, I replace those. I don't have any of those, but can probably scavenge a set for you.............

              On O-rings, I have all the ones for those carbs whereever they may go or whatever they may be called! 8)
              I've owned over 70 Katanas - you think I know anything about them?
              Is there such a thing as TOO MANY BIKES?
              Can you go TOO FAST on a bike?
              Welcome to! Click here to register


              • #8
                Missing o-ring in the #2 carb..


                • #9
                  Guess what??
                  I "found" the o-ring. It is worse for wear (new ones on the way) but seems to work. I think it actually got pushed into the carb some how.
                  All pistons are firing!! On to the next phase.


                  • #10
                    OK Phase two..
                    Carb syncro.
                    1-2 matched (fairly) 3-4 matched.
                    3-1 *shiver* the idle rises ever time I try,
                    bringing all the levels up. Idle adjustment fully out.
                    (Verified visually and I made sure nothing was stuck.) So I'm "chasing" bank 1/2 everytime I increase 3/4, 1/2 rises (with revs) if I lower it, it dies.
                    Another question. I have not plugged the vacuum line to the fuel cock. when I do the vacuum in # 4
                    pegs, it seems odd to leave it open thought.


                    • #11
                      OK you don't leave it open.. So why is the vacuum so high in #4? It couldn't be that far off.
                      but I'm guessing I need to try..
                      OK off to find a T fitting.


                      • #12
                        You need to plug that vacuum when syncing the carbs. Otherwise you have a vaccuum leak. (see below)Have you replaced the airbox? It will can make a difference.

                        Also I lost one of the O-rings below the vaccuum port on the air side. It will do exactly what you are describing when you try to sync, if you are missing one or have a leak in the air side. (by the air side I mean the Black top of the carbs)
                        AMA member # 224227


                        • #13
                          Good call, Meikol2 I was just thinking the same thing!! I did in fact remove all the covers last night.

                          I went in there looking for an o-ring to replace the
                          fuel mixture one. I remembered one of them was very tiny. I didn't find the o-ring I wanted but..
                          Opened a can of worms it seems.. Thanks bud!!

                          I bet I lost an o-ring or the diaphram seal..


                          • #14
                            I also found a broken spring in mine when I went to clean them and put in my jet kit. It had been sync'd around the problem, barely. Got a replacement from a salvage yard (didn't work), then one from Special K, along with a new set of those tiny O-rings for the sync ports. All of mine were less than perfect. Made a huge difference.
                            AMA member # 224227


                            • #15
                              Would you belive #4 was so badly tuned that it was about off the range??
                              So I nailed the tuning and got on the road!!
                              It's running great! A little clatter though so on to
                              valves we go.. Sigh it just never ends..