Rotax Hesitation Issue Help Required Please

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This topic contains 7 replies, has 4 voices, and was last updated by  Samir Shah 2 years, 4 months ago.

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  • June 8, 2016 at 12:38 am #66947

    Shane Spencer
    Participant

    Hi guys,
    I’ve just stumbled across the forum and wondered if any one can shed some light on an hesitation issue I’m having with my kart?
    Problem I’m having is the kart is really holding back and hesitating quite a lot, it seems be before the power valve opens, I’ve fitted these new parts to try to eliminate:
    New Power Valve kit
    Replaced the jet from a 165 to a 152
    New fuel filter
    New fuel pump internals
    New spark plug
    Charged the battery
    I did all these last week and the hesitation is still there, can anyone offer any info to help me out please?

    Thanks in advance.

  • June 8, 2016 at 6:31 am #66966

    tony zambos
    Participant

    Welcome to the forum.
    First, check your grounds. Then pull the carb and disassemble it. Take the needle valve out and clean the carb body thoroughly. Don’t get any cleaner on the needle valve. There is an internal fuel filter. Clean it out. Assemble the carb. Check for a float with fuel in it. Check the float heights. Last, be sure that the vent tube access the top of the carb has an opening in it.

    LAD Specialties customer / tony kart / rotax / kt100

  • June 8, 2016 at 7:15 am #66981

    Shane Spencer
    Participant

    Hi,

    Thank you for the advice, the only thing that I haven’t done on the list is check the grounds and the float chamber heights.

    To be honest I’m unsure how to check the heights?

    Thanks again.

  • June 8, 2016 at 7:26 am #66988

    David Cole
    Keymaster

    Shane, check you private messages. Thanks.

    David Cole - EKN Managing Editor

  • June 8, 2016 at 7:33 am #66989

    Shane Spencer
    Participant
    David Cole wrote:

    Shane, check you private messages. Thanks.

    Sorted the name change I think.

  • June 8, 2016 at 10:51 am #67002

    tony zambos
    Participant

    Use the link below to download the jetting and power valve article by John Savage. John recommends a 3mm float height. That’s a good place to start. I used 4mm but I come from a road race background.
    Note: you can download the article but you won’t be able to print it.

    http://www.karting1.co.uk/jetting-karting.htm

    LAD Specialties customer / tony kart / rotax / kt100

  • June 8, 2016 at 11:09 am #67003

    Shane Spencer
    Participant

    That’s a great link, thanks for that.

  • June 27, 2016 at 8:27 pm #67795

    Samir Shah
    Participant

    We’ve had an issue with the engine not revving consistently past 13k – Jr Max with EVO. I finally tried using 2 gaskets on the crank pickup. Amazingly, even on the stand, the engine sound changed, and it is now a lot better. We’ve only had 3 laps at the end of the track day with this change, so need to test it some more, but maybe worth trying.

    http://gorotax.com/information-bulletin-dellorto-ignition-system-how-to-assure-faultless-function/

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