Brief Hesitation When Full Throttle Applied

Discussion in 'Whizzer Motorized Bicycles' started by Hal the Elder, Apr 5, 2009.

  1. Hal the Elder

    Hal the Elder Member

    Hey Y'all...

    First, let me say that Oscar has never run better!

    Yesterday we crested Wadena Hill at 30 MPH...the best performance ever!

    However, there's the minor irritation of "stumbling" for about one second when I'm cruising at moderate throttle and suddenly open it wide. After the brief hesitation, full power returns and everything is Jake.

    Is this because the carburetor has no accellerator pump (like an automobile carburetor) to squirt a jet of gas into the intake to instantly handle the wide-open throttle?

    My 22mm carb has been modified to the following configuration:

    Restrictor plate opened to match the port opening.

    82mm Main Jet replaced the stock 90mm jet.

    Needle clip placed in 4th groove.

    My elevation is 3000 ft. where the atmospheric pressure is only 13.16 PSI.

    Thanks...
    HAL & OSCAR
     
    Last edited: Apr 5, 2009

  2. RdKryton

    RdKryton Active Member

    Hal
    You still have 2 grooves that you can try on the needle. Try the 5th groove first and if that makes it worse try the 3rd.

    Jim
     
    Last edited: Apr 5, 2009
  3. bill green

    bill green Member

    Hi Hal With what you have done your next step is to advance your ignition plate. This make the throddle control more agressive and in my case got ride of low end hesitation..Hope this helps..Bill
     
  4. Hal the Elder

    Hal the Elder Member

    HEY BILL:

    My throttle response is instantaneous and snappy! It's only when I go suddenly from part throttle to full throttle that the engine says "who, me?" for one second and then recovers.

    I would think that the problem is carb-related.

    Thanks...
    HAL
     
    Last edited: Apr 6, 2009
  5. bill green

    bill green Member

    Hi hal for the most part thats a fairly normal thing..It did help to advance my ignition to about 26 DEG.....Bill
     
  6. Hal the Elder

    Hal the Elder Member

    HEY JIM:

    With the needle clip in the 5th groove, it makes it worse...and it also sucks the tank dry with only 7 revolutions of the flywheel!

    AND THIS IS WITH A SMALLER MAIN JET!

    Will try the 3rd groove next.

    HAL
     
  7. RdKryton

    RdKryton Active Member

    lol Hal
    That's funny. Go to the middle groove this time. Good luck.

    Jim
     
  8. Hal the Elder

    Hal the Elder Member

    HEY JIM:

    The 3rd groove was the charm!

    Now I get good full-throttle response whether roll-on or snap-on!

    HAL
     
  9. RdKryton

    RdKryton Active Member

    Glad to hear it.
    Have fun.

    Jim
     
  10. bill green

    bill green Member

    Hi Hal Very Cool ..Have fun..Bill
     
  11. Hal the Elder

    Hal the Elder Member

    My Wadena Hill Performance Was Best With Clip In 4th Groove...

    ...so I'll go back to that setting and ignore the "brief hesitation". There was never any problem when I "rolled on" to full throttle anyway.

    HAL
     
  12. Hal the Elder

    Hal the Elder Member

    WAIT A MINUTE:

    Yes, with my needle clip in the 3rd groove, my full-throttle response now has no hiccups when I instantly snap it on from a lower-power setting.

    HOWEVER, my performance has dropped!

    With my needle clip previously in the 4th groove, I was able to crest Wadena hill at 30 MPH, the best I've ever done. Then when I went to the 3rd groove to correct my full-throttle hesitation, my hill-climbing performance dropped to 26 MPH.

    I now realize that I don't need instantaneous response when I snap-on to full throttle...I can get smooth, unhesitating response by just "rolling-on" the throttle, so what was I complaining about?

    The way I ride, with my favorite speeds in the 20-25 MPH region along the roads through my semi-rural neighborhood, why do I need instant full-throttle response? In fact, why did I need any of those performance enhancements?

    Well...I'm glad I opened my Intake, installed a Hi-Flow, had my Head Milled, advanced my Cam Timing, installed Mushrooms, changed my Main Jet, and all.

    I enjoy tinkering with Oscar, and it feels better that he has more power, which he truly needs at my 3000 ft. elevation!

    BACK TO THE 4TH GROOVE!

    HAL
     
  13. Hal the Elder

    Hal the Elder Member

    I went back to the 4th groove on my needle, and sure enough, my performance increased, and I crested Wadena Hill again at 30 MPH!

    After changing my clip from groove #2 (stock), to grooves 3,4, and 5, #4 is where my needle clip STAYS!

    I feel that I've got Oscar optimized for my High Desert elevation of 3000 feet!

    HAL
     
  14. Mountainman

    Mountainman Active Member

    Hal -- nice work there with Oscar

    Hal -- nice work there with Oscar

    been watching you all for a while
    as you have been working on your performance relationship
    good job done there

    have fun you two
     
  15. Hal the Elder

    Hal the Elder Member

    Thanks for your positive comments, Peak Person!

    HAL
     
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