Power boosting improvements include a new cylinder head with bigger valves, hotter cams and a new twin-injector fuel injection system. These are backed by a host of detail modifications that contribute to significantly increased power output, particularly at high rpm. To better suit the machine for non-modified stock racing classes, the transmission gets closer ratios similar to those of the racing kit transmission. 

Already rated as the top-handling chassis on the track - thanks in part to the class's only adjustable swingarm pivot - for 2004 the chassis benefits from feedback from our team racing bikes. New settings for the fork improve both damping and action, and a new coating on the fork inner tubes reduces friction for improved action when braking.

To complement the 04 6RR's racier performance, the bike sports a matt-black frame and swingarm, and a racy-looking lime-green drive chain. (You can clearly see the difference in the photo of the 2003 model above)

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.