How much difference does 37cc make?

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Motorcycle-USA just answered that question by putting the new, 636cc 2013 Kawasaki ZX-6R on the dyno next to the old, 599cc 2012 Kawasaki ZX-6R. The improvement is actually fairly impressive, and that’s before you factor in ABS and traction control.

As you can see, the differences don’t just come in marginal increases to peak torque and power, but throughout the engine’s mid-range, beginning at 6,000rpm. It’s between that and 12 or 13,000rpm where most riders will spend most of their time, even while going fast. Fatter curves there equal an easier time, less throttle lag and potentially even fewer shifts. Nicely done.

  • Jordan

    I think for the average rider, that extra 37cc makes a huge difference in how much more refinement you get out of the engine compared to a standard 600. Ultimately, the ecu of any sport bike is going to be severely restricted to meet emissions and noise standards. I think that notion explains why when the big 4 600s all shared identical bore and stroke they still had such different curves on the dyno graphs. Granted, there’s also possibly different timing, cylinder head port shapes, cam lift, velocity stack length, secondary throttle openings, primary throttle body width, so forth and so on which is a total compromised formula to give the best power and still pass testing without straddling a 100 pounds of catalyst to the exhaust and still be easy to manufacture. For bikes like the current R6, you could spend 3,000 dollars on a YEC ECU, matching harness, tuning and installation, etc trying to make an output similar to what the new Ninja makes, which Kawasaki takes a very practical method and just uses a little bit extra displacement. The rider remains oblivious to the extra width of the pistons and enjoys a much more useful output from the engine.

    I kind of wish the other companies would take note of this; it was a brave move by Kawasaki to go this route with the ZX-6. Then again, they are on the up and up in international racing.