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ZZR1200 carb problems

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  • ZZR1200 carb problems

    I recently serviced my bike, to include an oil and filter change, Iridium IX plugs and Pipercross air filter. Afterwards, the bike ran terribly popping and surging at low revs. I know that the Keihin carbs are a huge issue, with many riders pulling their hair out when trying to get them sorted. The bike ran perfectly well before I serviced it. That said, it can all be coincidental. I then decided to overhaul the carburettors, a job that I'm familiar with from my old ZZR1100 D3. I also thought it a good opportunity to rejet the carbs...and wish now I'd never bothered!

    So, I carefully dismantled and cleaned the carbs, using carb cleaner and compressed air.The carbs were in excellent condition..no residue or gum was seen. I then fitted a 6Sygma Racing jet kit, (new pilot and main jets), fitted new float needle valves, shimmed the needles and installed a new fuel filter. I also checked the float levels, all within tolerance at 13 mm. As per most on this forum having carb issues, I set the pilot jets (idle mixture) at 2.5 turns out; however, the bike was awful to ride at anything below 4000 rpm. Kawasaki recommend setting the jets to 1.5 turns out, which I have tried. After careful balancing using a Carbtune, the bike seem to tick over well and rev freely. Unfortunately, it was still crap on the road and got worse as the journey took on distance.I intend to continue experimenting with the idle jets, turning the screws out one quarter turn at a time. Balancing is not an issue with me, and this bike seems to balance well.

    After all said and done, I'm thinking about the HT circuit or coil (s) breaking down, as it is possible when I renewed the plugs that a cable gave up when repositioned. Connections to the coils are good. The fuel pumps seems to be working well. All cylinders seem to be firing...but, on the road, it just runs like a sick dog. 6Sygma recommend turning the pilot jets out three turns as a baseline; however, I do not think this adjustment will hold, as the springs are on their limits of maintaining tension in the jet housings. And, yes, I was careful to ensure the correct way round for the pilot needle O-rings and little washers! It sure got me stumped at the moment! I suppose it is all a process of elimination, as usual (and, as an ex-car mechanic, I know this well) and until I fit new HT leads and/or coils I can't go much further.

    So, apart from that stated above, what to do next? Cheers!

  • #2
    I would add that I also fitted new float bowl gaskets and the diaphragms are all in good condition and carefully installed.

    Comment


    • #3
      Is this all you did initially to the bike?

      "I recently serviced my bike, to include an oil and filter change, Iridium IX plugs and Pipercross air filter".

      And afterwards it started to run bad?

      If it is, I would put the old plugs back in and see.

      I also serviced my bike, valve job, plugs, air cleaner etc.

      Then it did not turn over...matter of fact, my cluster lights were funky...anyway, it turned out to be a wire underneath the tank right where 2 harnesses plug into each other.

      The wire corroded off the connector and I had to rewire it.



      dinky,

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      • #4
        Heh Dinky...

        Yep! That's all I did...I am increasingly thinking HT leads/plugs as obviously these were disturbed and may have gone West. I also overhauled the carburettors, as stated in my original post. However, I don't think this is a carb problem as the rough running is still there as with before I worked on the carbs. I used the newer iridium plugs...so, good idea of yours to put the old plugs back and take it from there. I can also check the colour of the plugs... Otherwise, it could possibly be fuel starvation - maybe the petcock needs checking although it appears to be working normally. Will have to wait till Monday, anyway.

        Dave

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        • #5
          I looked at getting iridium plugs awhile back but stopped, and I think it was because i read someone had issues.

          I try to use stock parts when I can, and I'm not sure there's any benefit to using iridium...at least none that I've read.

          It could also be coincidence that something just happened like it did for me.

          Good luck, hope you figure it out.

          dinky,

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          • #6
            My ZZR1200 ran better on Iridiums, as does the R1. I very much doubt that's the problem, but it's easy enough to check you don't have a bad plug by refitting the old ones.

            Definitely worth checking the plug leads where they go into the coils and caps.
            "You don't get slower with age, you just get more cautious." Michael Rutter

            06 Ocean Blue ZZR1200, the coolest colour.
            99 Yamaha R1

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            • #7
              i have a problem,had bike tuned back in feb.set for about 2 months than tried to start it and ran very poor ,back firing and missing,got it running good and it ran fine for acouple of weeks,came back from a ride and next day it bearly ran and then stopped and it will no longer start. any help

              Comment


              • #8
                So, here’s an update. With bike inexplicably running rough after a service, and later carb overhaul, I changed the HT leads and set about putting back the old plugs, as suggested by Moise in this thread. I found one of the Iridium plugs had somehow closed to a zero gap! Can’t think how this happened but, s*!t does happen sometimes...☺️. I also backed out the pilots from one half turn to two turns out. After a quick rebalance, the bike is now purring smoothly with no hunting or popping. Need to do a long ride to confirm all is well...but here’s hoping!

                One other point, after all seemed well, I was suddenly hearing a “ticking” noise adjacent to the right hand coil and, as soon as this started, the bike ran rough. When I moved the loom to and fro, the ticking stopped and the bike ran smooth. As it seemed to be coming from the main loom, I undid the tape and chased the coil feeds in the loom, checking for bad wires - but nothing found. Weird! I bundled the wiring back together, wrapping it with pvc tape. All seems fine now. Deffo is not the HT side. Hate mysteries!
                Last edited by Bombardier; 09-23-2018, 12:20 PM.

                Comment


                • #9
                  Glad you got it sorted.

                  I hate chasing fuel and/or electric issues.
                  I have neither the time,or the inclination, to explain myself to a man, who rises and sleep under the blanket of the very freedom that I provide, and then questions the manner, in which I provide it. I'd rather you just say 'thank you' and go on your way.

                  Comment


                  • #10
                    Originally posted by zzrider76 View Post
                    i have a problem,had bike tuned back in feb.set for about 2 months than tried to start it and ran very poor ,back firing and missing,got it running good and it ran fine for acouple of weeks,came back from a ride and next day it bearly ran and then stopped and it will no longer start. any help
                    Probably the carbs are dirty/clogged. Maybe a bad fuel pump. First, make sure there is fuel in the fuel tank, and that it is gasoline.
                    How To Cheat on Personality Tests
                    1. When asked for word associations or comments about the world, give the most conventional, run-of-the-mill, pedestrian answer possible.

                    2. To settle on the most beneficial answer to any question, repeat to yourself:
                    (a) I loved my father and my mother, but my father a little bit more.
                    (b) I like things pretty well the way they are.
                    (c) I never worry much about anything.
                    (d) I don't care for books or music much.
                    (e) I love my wife and children.
                    (f) I don't let them get in the way of company work.
                    From <cite>The Organization Man</cite> by William Hollingsworth Whyte, 1956

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                    • #11
                      Originally posted by reidmct View Post

                      Probably the carbs are dirty/clogged. Maybe a bad fuel pump. First, make sure there is fuel in the fuel tank, and that it is gasoline.
                      Good call, Reid. Also if you switch to reserve with old fuel to start with, That's where the sediment collects.

                      KN, this ride's for You.

                      http://i415.photobucket.com/albums/p...ps2ecwj35m.jpg

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                      • #12
                        So, I took the bike for a longer spin - mega! Super dialled-in now, she unleashes like a scalded cheetah. Super smooth tick over too, burbles nicely. ????

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                        • #13
                          What did you wind up doing to get it to purrr.

                          Jets? Pilot Screw turns, etc.?

                          dinky,

                          Comment


                          • #14
                            Hey Dinky,
                            Remember the carbs were rejetted using a 6Sygma kit, shimmed needles too. I wound out the pilots to two turns from OE spec of 1.5 turns out. Put old plugs back in, as were good anyway. New HT cables - easy job. Balanced using Carbtune. Still got the problem of a blowing headlamp fuse...frightening at night!

                            Comment


                            • #15
                              Originally posted by Bombardier View Post
                              Hey Dinky,
                              Remember the carbs were rejetted using a 6Sygma kit, shimmed needles too. I wound out the pilots to two turns from OE spec of 1.5 turns out. Put old plugs back in, as were good anyway. New HT cables - easy job. Balanced using Carbtune. Still got the problem of a blowing headlamp fuse...frightening at night!
                              WOW, so 3.5 turns out on the pilot.

                              Those HT cables, is it just cut to length, and screw in on both ends?

                              That blowing headlamp seems scary also....

                              dinky,

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