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  1. #1

    900zxi falls off at 3/4 throttle

    A couple weeks ago, I started having issues once I hit 3/4 throttle.

    It seems okay up to that. It gets up to about 6600 RPM if I keep it just below 3/4. Above it the rpms drop off pretty fast.

    I had it set to 1 1/4 low and 3/4 high.

    I changed it the high to 1 turn but I still have the isse.


    Engine and carbs were rebuilt last year. Compression is at 120 on all three cylinders. It running fine a couple weeks ago.

    Any suggestions?
    Anyone have carb setting for a 900 zxi?


  2. #2
    If you haven't already I would check the fuel filter, the pick up in the tank and the tank vent valve.

  3. #3
    Rodsatheart's Avatar
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    Sounds like there might be some crap in the metering circuit of one of the carbs or the inlet filters are restricted a bit.. Did it change at all when you turned them out ? Looks a tad rich on the low speed screws, but if it likes them there, leave em. Have you tried applying the choke a tad to see if that helps ?

  4. #4
    I replaced an external filter outside of the tank and cleaned the small filters in the carbs. I have not pulled the ones in the tank.

    Roddaheart, last weekend I pulled the choke and it seemed to improve. As a result I turned the screws out from 3/4 to 1. I was planning to go to 1 1/4 out today.


    The low end seemed a little week so I turned that out too. I think I may turn them in. It doesnt seem to be loading up but there isnt a lot power.

    The factory settings I found online for the 900 were all over the place but non of them were jver 1 turn out on the high speed screws.

  5. #5
    steve45's Avatar
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    If it used to run good, then starts running lean, then you either have trash in the fuel system or an air leak. Adjusting the mixture screws is like putting a band-aid on a broken leg.

  6. #6
    I turned in the low screws in to 1 turn and the high out to 1. Started having issue on the low end but high end was a little better.


    I then turned the lows back out to 1 1/4 and the highs out to 1 1/4. It ran pretty good. No issues with flat spots or rpms falling off.

    I think I could turn them out and get a little more out of it but as Steve pointed out there may be an air leak.

    I am thinking I should do a leak down test.

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