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  1. #1
    CB750 New Member Slow4's Avatar
    Join Date
    May 2019
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    MN
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    2

    Let's talk exhaust systems

    Admittedly I'm new to 4 cylinder bikes, but I have a 4 into 1 supertrapp system on my 84 nighthawk, and I'm noticing a serious flat spot between 3-6k rpm's. I was told by one shop that the 4into1 systems were really only good for high rpms. Is this accurate? I'm wanting to get some more power in the lower range where I'm really doing my riding. I don't think the carbs are properly synced yet, it seems to be running rich. But before i spend a bunch of money on tuning I want to make sure I've got the best system for what I'm after

  2. #2
    CB750 Guru amc49's Avatar
    Join Date
    Sep 2015
    Location
    Fort Worth TX.
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    2,433
    Well, you are not going to do much other than kill a motor pre-designed to make power at higher rpm anyway. If running rich due to people rejetting maybe you should rethink some of that, CV carbs typically run well using the same jetting as before the header as they self compensate for jetting somewhat.

    Running too rich makes them choke (flat spot) on a hard demand for more power, a CV symptom if there ever was one. Older engine with lower compression has the same effect.

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