2013 ZX6R returning to a 636 engine?

blackster how do the 2013 636 stats compare to the previous and last 636 the 2006 model, have they refreashed this motor or would it be a new design?

The only similarity with the 05-06 motor is the capacity. From 07 the motor (whole bike for that matter) was completely new. Since then it's been tweaked along the way.

The bore & stroke, compression ratio of both bikes are very similar and the injection is identical.

06" 636

Bore & stroke = 68 X 48mm
Compression ratio = 12.9:1
Injection = DFI with Keihin 38 mm (1.5 in) Throttle Bodies (4)

13" 636

Bore and Stroke: 67.0 x 45.1mm
Compression Ratio: 12.9.0:1
DFI with Keihin 38 mm (1.5 in) Throttle Bodies (4)

All four of the primary header pipes are interconnected on the new bike, there claiming by doing this it improves bottom end & mid range torque.