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  1. #1

    720 with novi carbs

    I have a race version 720 big bore 175lbs compresion pretty much done to the max,last year it bogged out till one day something let loose and finally top speed(and it was cleaned and checked by a profesional but still bogged till it broke loose)this year it is worse,I checked the screens in the carbs,cleaned the filter,starts to let go for a second then bogs again,If you give it full throtle it will usaually bog,any ideas?only about 4 hours on this since new,also back cylinder plug seems a little wet and black..


  2. #2
    compression good on both cylinders?

    Because you have went away from stock settings...you MUST learn carb tuning. low speed jets, high speed jets, low speed adjusters, high speed adjusters and pop off pressure need to be your best friends!

    1. Does it idle good?
    2. If you crack the throttole does it bog or pull.
    3. When you are going along at 50% and pull it...what does it do.

    Seriously though...start reading carb tuning by Group K and Factory Pipe.

    I just tuned my 720 swapped GTX and it rips but then again...it's a stock setup. You will have some battles to overcome.

    Good luck,

    Jason

  3. #3
    idles good,just acts like something is pluging up,if you play with the throtle at about half you can get it up to speed like it sudenly breaks loose,yesterday it broke loose for about ten minutes then back to the bogging out,will dismantel the carbs completely this winter,maybee a bad fuel pump?

  4. #4
    Connecticut CrazyA's Avatar
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    Possible intermittent electrical issue ?

  5. #5
    Myself's Avatar
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    Broken waterbox baffle or collapsing exhaust hose?

  6. #6
    Quote Originally Posted by Myself View Post
    Broken waterbox baffle or collapsing exhaust hose?
    how to tell if it is one of those?I just bought a 63 liter/hr fuel pump hoping thats it,being intermitent though it may not be one of those but it never hurts to check,thanks. notice I said thanks to myself.

  7. #7
    Myself's Avatar
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    Take the waterbox loose and shake it. If anything is rattling around that's bad. While it's out pull the main exhaust hoses loose and look through each one. Normally if a hose collapses internally you can feel a squishy/soft spot when squeezing the hose.

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