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Good idle and lower RPM but hesitating over 3K RPM

Discussion in 'CVP Stage 1 Tuners Kit' started by siffordd, Jul 7, 2013.

  1. siffordd

    siffordd New Member

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    '04 Twin Cam with the 95 inch kit. Big Sucker intake kit and Bub Stealth 7 exhaust. Installed CV Stage 1 Tuner kit. 48 / 195 on the jets. I had also installed the new spring and carefully drilled the slide with the bit provided.

    Seems to idle well. EZ mixture screw has no effect that I can discern. No idle change screwed in or out. Confirmed that o-ring was in there.

    Runs well at lower throttle settings with little problem accelerating. Over 3000 RPM I get a hesitation or stumble. Another twist of the throttle gives a surge (good accelerator pump) but when it goes steady state anywhere over 3K , I get the hesitation / surging again.

    Got back and checked for leaks with propane. No effect so assume manifold seal is good. Wondering after a little reading on the forum if the slide surgery and spring might be the problem.

    Thoughts? Thanks for your insights.

    Siff
    siffordd, Jul 7, 2013
    #1
  3. kenfuzed

    kenfuzed Administrator Staff Member

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    On a 95" with free flow air cleaner and exhaust you may want to move up to the 200 main jet. An exhaust leak at the head pipe flanges can also contribute to performance issues while at cruise speed.

    Sometimes on a Twin Cam (88 or 95) it is difficult to sense any change with the mixture screw because the ignition is compensating. Try lowering the idle to just above stall and keep turning the mixture inward blipping the throttle each turn until you can find where it hesitates. Then adjust outward by half a turn.

    Double check the needle jet (stainless nozzle) is installed correctly. Picture of this in the link below.
    Harley CV Carburetor - Tuning Issues and Troubleshooting
    kenfuzed, Jul 7, 2013
    #2
  4. siffordd

    siffordd New Member

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    OK Ken, so a follow-up. I went back and double checked everything and installed the 200 jet as recommended. When I was in there I went ahead and checked the needle jet and while it was in the right orientation, I'm convinced that it wasn't seated correctly that first time. When I put it all back together the jet stuck further into the venturi airflow area.

    I went ahead and took out the plugs and cleaned them to get a fresh sense of tuning. After warming up and trying to tweak the EZ Mix setting I rode it for a while. Entire thing ran much better with no hesitating or problem anywhere in the throttle setting. Seemed to run pretty good but was still wondering about the fine tuning.

    I rode for the week (~140 miles) and then pulled the plugs today to see how they looked. Dark and sooty looking. Suspect things are a little rich. I was careful not to overly use the enricher during the week.

    I would like a little direction on things to check. Looking at the forum my guess in order of things to check:

    Ensure enricher not binding or or stuck partially open
    Work with EZ on air mixture to try and lean it out (still fairly insensitive to setting)
    Go to a smaller jet?

    Anyway, your insights are welcome. I feel like I am ever so close.

    Thanks

    Siff
    siffordd, Jul 20, 2013
    #3

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