Home Forums 2-Cycle Racing HPV clutch/carb issue

This topic contains 5 replies, has 5 voices, and was last updated by  John Gay 5 years, 5 months ago.

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  • #3910

    Kirt Burcroff
    Participant

    We’re running a brand new non-blueprinted HPV this season. We can’t seem to get any power at the low end, like pulling out of the pits or at the drop of the green flag. We’ve tried starting out with the low needle at 1 turn and easing onto the throttle but the engine bogs down to almost stalling. I’ve been told the clutches can’t be adjusted and we’ve tried a different carb but it still takes a half lap of crawling before we can start getting above a crawl. The kart is set up for HPV 2/320lb Komet Jr. Class.

  • #3943

    Roberto Perez
    Participant

    Try This..
    Start with the LOW speed needle at 1 1/2 turns when you drive into the track, once you are on the track , open it to 2 or 2&1/4 … but you must do that every time… I do not know the reason behind it.. it just works for me
    High is at between 1/4 or 3/8

    I hope this helps.

  • #4190

    Kirt Burcroff
    Participant

    Thanks Roberto,

    We’ve been playing with low needle settings for a few race days and still can’t seem to get the Kart moving to leave pit road or take a green flag. Once it’s going it’s pretty good. I could walk faster than the kart moves for the first lap or so. We’ve tried different carbs and still no power at low end. It’s almost like the clutch is grabbing too early and bogging the motor down.

  • #4311

    Chad Hendricks
    Participant

    Check the copper ground wire that is attached to the coil. I was having the same problem with my engine bogging at the start and it took forever to get up to speed. I rebuilt the carb twice, I changed the carb, I changed the air filter, I messed with the needle settings, I was about to start adjusting the clutch when I finally noticed that ground wire was very loose. So I removed the coil, tightened it down, and the next time out the engine ran awesome. Give it a shot and good luck.

  • #4315

    Troy V Smith
    Participant

    Not much of a TAG guy these days, but you might want to check your clutch condition/settings . Are you running the EXPD or shoe type clutch? We had a similar problem at the Robopong (Roberto!) and it turned out that one of the shoes had broken – at speed you’d never notice the problem but really, really hard to get going, if at all.

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  • #10827

    John Gay
    Participant

    I had the exact same symptom and I’m in the Komet Sr class.  After trying several carbs, and at the recommendation of Franklin Motorsports, I put on a new coil and the issue was taken care of.  The kart now had power like I’ve never had before coming up through the rpm’s and also previously, during the pre-race formation lap, the kart could barely stay running.  Now, it’s no problem to run that slow of a speed with the needle at 1 1/2 turns approaching the green flag.   Also, make sure the ground strap from the coil to the motor is tight.

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