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Help Acceleration Issue - 1990 ZXR250R

Discussion in 'Kawasaki 250cc In-line 4's' started by Sweeks, Aug 28, 2021.

Page 7 of 7
  1. Sweeks

    Sweeks Active Member Premium Member

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    Joined:
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    Location:
    Alabama, USA
    My Bike:
    1990 Kawasaki ZXR250R, 1984 KR250, 1973 Z1, 1972 H2, 1973 H1, 1973 Bighorn
    Hi Tony,
    It’s an SP, freshly built top end.
    New: rings, reworked head with all new valves, new timing chain, guides, tensioner.
    COP mod. I have rebuilt and installed a standard A set of carbs with stock needles, jets, and set up per manual. I have the SP carbs but was trying the A carbs for comparison.
    New float needle and seats. New diaphragms, new carb holders, Litetek seals ( carb to airbox)
    Stock (original) exhaust.
    New water pump, thermostat.
    I took it out for a spin Sunday. First real ride and I kinda got used to the bad spot at around 6k.
    I learned that, if I take off and go through the gears aggressively, I can work around the problem.
    It actually impressed me with its acceleration.
    I was just beginning to enjoy the ride, right up until it blew the head gasket. I guess that’s what I get for not re-torquing the head. Lots of disassembly to do that.
    I haven’t torn it down yet. I’m getting some of my other bikes ready for our week long bike meet at The tail of the dragon. (Google it, if your not familiar)
    I’m going to take three bikes, was hoping to take the ZXR, but definitely taking the KR, it’s one of the most fun bikes I have.
     
    • Bummer Bummer x 2
    Sweeks, Apr 26, 2023
    #121
  2. Sweeks

    Sweeks Active Member Premium Member

    Messages:
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    19
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    178
    Joined:
    Apr 5, 2020
    Gender:
    Male
    Location:
    Alabama, USA
    My Bike:
    1990 Kawasaki ZXR250R, 1984 KR250, 1973 Z1, 1972 H2, 1973 H1, 1973 Bighorn
    Oh, I made my air filter element with Unifilter foam.
    Here’s the dimensions if anyone needs it. Use trim adhesive to assemble.
    upload_2023-4-25_18-14-37.jpeg
     
    • Like Like x 1
    • Nice Work Nice Work x 1
    Sweeks, Apr 26, 2023
    #122
  3. TonyZXR

    TonyZXR Well-Known Member

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    My Bike:
    GPX250, ZXR250A, ZXR250C
    I've found you can usually improve that flat spot with adjusting the pilot screw. My bike with a aftermarket exhaust seems to run best with the pilot screws 2.75 turns out .
     
    • Like Like x 1
    TonyZXR, Apr 26, 2023
    #123
  4. Sweeks

    Sweeks Active Member Premium Member

    Messages:
    50
    Likes Received:
    19
    Trophy Points:
    178
    Joined:
    Apr 5, 2020
    Gender:
    Male
    Location:
    Alabama, USA
    My Bike:
    1990 Kawasaki ZXR250R, 1984 KR250, 1973 Z1, 1972 H2, 1973 H1, 1973 Bighorn
    That’s interesting, I will experiment with that, once I replace the head gasket
     
    Sweeks, Apr 27, 2023
    #124
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