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  1. #1

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    1999 1100ZXi bogging on throttle snap off idle

    Hi everyone. I need some help from a carb specialist. My 1999 1100ZXi (CV carbs) has a hesitation or bogging when when I snap the throttle from idle. Had cold start problem, but thats fixed already. Everything is stock on the ski. It will not completly die, but bog for a second and then take off. After a good time of hard running it almost goes away, but if it idles for a bit it will come back to the same thing.

    Here is what Ive done so far. At first it had a cold start problem even with choke on, along with a serious bog on acceleration off idle. After a good minute of cranking it would start. I opened up the carbs and found idle jets clogged in 2 of the carbs. Cleaned out all the jets. Left pilot screws at the original settings. (plugs were still in place) Test ran and still had bog, not quite as bad but still there. Then i dissassembled again, inspected jets, all clear. I popped out the sealing plugs for the pilot screws and opened each a 1/4 turn. Also I tried to test pop off, but I'm not sure if I fully understand this concept. I can not find in the manual the pop off pressure spec. I found specs for ultra 150 15.6 psi and took that as my spec. I found pop off to be about 22 to 25 psi. But it seems the needles start too slowly leak at about 18 psi. I use a hand pump and its a hard to get the needles to pop. I bent the float arms a little, but didnt see a noticeable difference in the pop off pressure. Reinstalled everything and test ran. Runs better but still has hesitation on throttle snap from idle. Also now it seems its a little rich at around 1/4 to about 1/2 throttle. What is the next step to do? I have a 2000 Ultra 150 and it will respond instantly to full throttle snap from idle, even when its cold. It also runs a lot smoother at 1/4 to 1/2 throttle. Any ideas appreciated.

    Thanks for reading,

    Willie
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  2. #2

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    I guess nobody familiar with this problem.

  3. #3
    dghal's Avatar
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    The forum sometimes gets quiet during holidays and the off season,, I am not familiar with the CV carbs but sounds like it could be lean, Any back firing occuring??

    In time some one should post info on the carbs

  4. #4

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    No backfiring. Been riding a few times last week. It seems rich at idle. I was able to start it in the morning after a few days sitting with no choke. Fired up with just one touch. Before it would crank forever even with choke. So now I'm wondering if it might be loading up? Also when running at full throttle for like 5 minutes rpms will slowly drop from a little over 7000 to just over 6000. If i slow down to half throttle for half a minute it will again hit 7000 rpms. I slightly pulled the choke when rpms fall and it seems to worsen. I did jump the engine compartment temp sensor to keep timing advanced. It seems to be a little more responsive after, but still hesitates a second before it will take off.

  5. #5
    seaobin's Avatar
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    How do the plugs look when you have idled into the dock. If rich, they will be oily. What do your piston crowns look like? Check your wash.

    When you hit the throttle and it bogs, if you pull the choke what does it do?

    sounds like you could have a small leak in your carbs allowing your crank case to load up a bit.

    WOT issue sounds more like a clogged fuel tank pressure issue

  6. #6

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    I need to do some proper plugs reading. They dont seem wet but thats the day after riding. They do look kind of dark. Next time out I will take my camera and take some pics at the lake. Wide open cut, half throttle cut and idle. Can you explain what you mean by WOT issue sounds more like a clogged fuel tank pressure issue I did loosen the gas cap a little last time out but it didnt seem to make a difference.

    Thanks for the response,

  7. #7
    If your fuel tank breather clogs or the valve breaks, you get fuel stavation and it dies or loose power.Try sucking through the tank breather line.

    The low end and top end probs dont really sound linked to me, unless there is crap in your carbs and then they do all sorts of things. Other probs like deteriorating diaphragms would not help.

    If you have your timing advanced, you need to richen it off the bottom, perhaps by more than just 1/4 turn. Presumably you bent your pop arm out to lower your pop pressure? If it hesitates off the bottom cold, its lean. I have had that prob which goes away when its warm. My theory was the jets get bigger as they get hotter and it gets more fuel. Either way it was lean.

    If you cant sort it and everything else looks ok, perhaps buy new diaphragms, new needles/seats and springs, clean your carbs and install them, then see if that cures it.

    Presumably your pulse line is in good shape and your compression is good.

  8. #8
    Moderator DrewNJ's Avatar
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    Be careful with making adjustments on the CV carbs if you don't know what your doing. I have done SEVERAL sets of carbs but don't feel comfortable with the CV's.. The screws are air screws, not really the same as a conventional carb. IIRC backing the screw out leans it out??(opposite of let's say mikuni's)..... Again, find someone who knows the CV carbs specifically.

    By what you are describing it sounds like a lean condition.

  9. #9

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    1100ZXi Engine toast!!

    Well I have an update again. Engine is toast. I attached some pics for comments. Anybody have an engine forsale? Or parts to rebuild this one? Need crank, cylinder or maybe it can be sleeved. Crank case can be welded.

    Was riding this weekend. Ran very nice except for still bogging on take-off. Ran till I almost finished a tank of gas. Hit a nice wave and as I was airborne and engine free revved, I heard the grind and then death. The piston was damaged - scoured from water ingestion from cracked exhaust elbow. This was first time riding after exhaust pipe replacement. The sleeve was not damaged though.
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  10. #10
    Moderator DrewNJ's Avatar
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    damn..sorry to hear man.

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