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Low power at higher revs.

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  • Low power at higher revs.

    I feel like my bike is just as fast when accelerating from 70 mph. Doesn’t matter if I’m in 6th or 3rd. It feels like there is no power at the upper ranges of the revs. It seems grunty and torquey at the lower ranges of the revs but doesn’t have that “top end rush”. My valve lash is good. The carbs are clean. I have done a bunch of things to this bike (new plugs and new fuel hoses) I can’t figure out why it feels this way. Maybe it’s just me?

    I am a fat bastard, I’m 280 lbs, could that be it? I’m just too fat to make this bike go fast? Any help is greatly appreciated. Even “go on a diet fatass”. lol. THank you all.

    2003 ZZR1200, 4K miles. New plugs, plug wires, carb rebuild kit, jet kit, no brake problems. At my wits end.

  • #2
    Eat more of those New Mexico chillies!

    Seriously, what size main jet is in there? (OEM is 150).
    I had my patience tested. I'm negative.


    • #3
      Hello Bill, it’s got 150 Jet installed when I put in a dynojet jet kit.


      • #4
        Lack of power at higher revs usually indicates an insufficient fuel supply, or lousy air/fuel mixture.
        I assume your fuel filter is good? How about the slide diaphragms - they move up and down with ease?
        Blockage in ram air?
        Just some ideas.
        I had my patience tested. I'm negative.


        • #5
          I'm leaning toward something BillDownUnder said regarding the ram air tubes. Make sure the equalizer tubes that feed the float bowls are not blocked, kinked, disconnected, etc. If any of those conditions exist, the ram air pressure will keep the fuel from rising up the main jet.


          • #6
            I had a similar problem after last year's DIY carb refurb. Took it to a local independent guy. Pinched diagram on carb 1 and a slide issue. All good now except for very slight hesitation off idle.


            • #7
              Thank you all for your responses. I did find a few things that might have caused the issue. I had a pinched float bowl oring and also a crappy oring in one of the tubes that goes in between the carbs, not the fuel lines the other ones. Anyways the bike feels better now, not 100 percent but I think that’s because I’m a fat bastard. The next mod I need to do is lose weight.

              this community is really very special and you all are awesome.


              • #8
                Good news!
                Like I said, more New Mexico chillies - fire up the metabolism.
                I had my patience tested. I'm negative.