This is what have been done with the 2004 model:
Reshaped combustion chambers and redesigned
piston crowns help produce more power. Molybdenum coating added to piston skirts to
reduce friction and mechanical loss, contributing to the ZX-6RR’s high-revving
nature. Intake and exhaust valves are larger for better
breathing at all rpm. Camshaft profile has higher lift for more
performance. Gear ratios for the oil pump changed to reduce
mechanical loss. Cut-outs added to the cylinder skirts to reduce
pumping loss . Crankcase is light and rigid, allowing piston oil
jets to be positioned closer to pistons Short intake and exhaust valves reduce weight and
improve high-rpm performance. Larger intake valves help increase performance. Single springs of oval-shape are lighter
providing improved intake valve control at high rpm. Stepped spring seats replace previous plain type
to better stabilize the valve springs.
Large-bore 38mm throttle bodies produce high
engine output and low emissions. Sub-throttle bodies ensure smooth, linear power
characteristics. New twin injectors improve cylinder filling for
more power. Six-Speed Transmission w/Clutch Back-Torque Limiter
Closer gear ratios for 2004 provide for more
aggressive, competition-style performance
Fully adjustable fork runs stiff tubes for high
fork rigidity and superior steering feedback. Top-out springs and adjustable spring preload are
fitted for stable performance throughout the stroke range. Super-hard DLC (Diamond-Like Carbon) coating
added to inner fork tubes to reduce friction. Revised damping for improved action
Nitrogen-gas charged Kayaba shock with piggyback
reservoir is fully adjustable for rebound and compression damping. Shock utilizes a threaded collar spring preload
adjuster. A top-out spring on the rear shock improves shock
action. Steeples damping adjuster with check valve
instead of needle valve for improved damping. Adjustable ride height with 1mm shims.