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Discussion in 'Modifications and Projects' started by typhoon, Oct 18, 2006.

  1. ...and noisier and torquier and more fuel efficient and better throttle response! All from something I had to replace anyway! And even better when they are second hand, but almost new!



    I would have to describe the sound as sublime. There's something about a Kawasaki four and dual exhausts....

    Regards, Andrew.
  2. Yes. Have you taken the restrictors out of the carbs yet?
  3. Tell me more please. I have never heard of restrictors in the carbs of 1000GTR.
  4. I've owned 2 GTRs. My 1986 model was fun,
    but when I got my 1995 model it seemed weak. Many years had
    passed and I thought it was just me riding faster.
    Eventually I worked out it wasn't.
    I knew my '86 would do 200+kmh, and my 1995 felt weak
    and struggled at only 160kmh.

    It turns out, some years of Australian GTRs have restrictors
    for the noise laws. Can you say goodbye to about 20 horsepower?
    I think it is '89 onwards, but
    I'm not 100% exactly certain on the date.

    The carbs are a biatch to get in and out.
    If you don't have the carbs out of the bike you will not have to remove
    them to get the restrictors out.

    If you do have the carbs out already, slide the vacuum slides
    (part 16126 in the diagram) up and
    down with your finger inside the carb.
    IF the slides go up all the way, you aren't restricted. If some
    of the slide still shows (blocking the carb throat) when the slide is up
    as far as it goes, then you are restricted.

    Remove the black plastic-looking carb tops
    (actually they are made of a resin)
    which are part # 16005 in this:

    Turn them upside down and look inside.
    You will see a pin in the middle that the spring sits on.
    Surrounding that pin you will see nothing (unrestricted) and the cap will
    be only a few mm thick, or else, 4 raised ridges that are moulded into
    the cap and make it about 10mm thick (restricted).

    The raised ridges stop the slides from opening all the way, effectively
    limiting your bike to about 2/3 throttle maximum.
    If you grind away these ridges with a die grinder, or buy a set of
    unrestricted carb tops from an '86 model at a wrecker,
    you will gain about 20hp. My bike showed a very large increase
    in power from this mod.

    (Dear EPA/Police Person: I am assuming the readers are racing
    or for show, because to modify the noise control
    is probably illegal on a road bike;
    of course I install some restricted carb tops when I ride on the road).
  5. I heard you can replace with GPX250 bits as well... Or I could be dreamin'.
  6. I'm sure there are a lot of Kawasaki's that use 32mm Keihin carbs,
    the tops are pretty interchangeable. GPX250, eh?
  7. I like the sound of the free option. I did know about the carb stops in the carb tops, but haven't done anyting about it yet.
    I plan on using my router to mill the stops out.
    Mind you, the bike goes hard enough for me at teh moment, I might do the mod when I need more! :cool:

    Regards, Andrew.