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kawasaki Zx7r ..aftermarlet muffler/rejetting/mods

Discussion in 'Technical and Troubleshooting Torque' started by rayzrider65, Sep 18, 2008.

  1. Hey guys,I have bought a zx7r it's a 1996 model 26k,has a aftermarket muffler.the guy i bought it off said just use a little choke..which I did for the first 10 rides..a couple of days ago I thought I will just use the choke fully and see how it goes..shhhhhhiiiiittttt.half aclick up the road the bike started to miss on 2 cylinders,,it really scared me,thinking I had blown the engine..the choke was off at this point..I thought just keep goin and get to work..luckily 4km later the motor fully kicked in..So I suspect the motor was flooded with choke on,and soaked the plugs
    ..So does a change in back pressure(muffler) really affect the way starting needs to be done,I had a zx6r with standard everything and it needed the choke everytime,anyway in future i am reluctant to use the choke on this bike unless really neccessary..

  2. It's been a common practise for many mechanics over the years to fit slip-on mufflers and then "over-jet" the engine.

    It accomplishes nothing more than poor low speed running and excessive fuel consumption. (Not to mention poisoning my kids planet!)

    You SHOULD need to use the choke on a cold morning to start a correctly tuned 4 cylinder motorcycle.

    I'd start by returning the carburettor settings back to standard. You'll probably find the needles have been raised. Richen the idle/air bleed screws by half a turn and fit some new plugs.

    That should give you a good baseline setting.