Launched in 1987, the Honda CBR600F was the lightest 600 cc motorcycle available at the time, weighing in at only 396.8 pounds. The bike was the first to implement a full-body covering chassis with a liquid-cooled inline 4 DOHC engine delivering 83 BHP at 11,000 RPM. The engineers at Honda undertook expensive and extensive development on the engine, due to the cost reduction offered by eliminating expensive cosmetic upgrades to the engine. It had a 6 speed gearbox capable of a top speed of almost 140 mph. The 1990 CBR600 F received its first upgrade, starting with the engine, christened the CBR600 F2. The overall engine displacement had increased to 600 cc from the earlier 598 cc capacity with an increased power delivery of 100 BHP at 12,000 RPM. Other modifications included the new stainless steel exhaust system, modified camshaft timing, re-structured engine pistons and combustion chambers (evident from the volume capacity), latest ignition, and carburetor settings for optimal fuel and air mixing ratios accompanied by a higher compression ratio. The combination of changes raised the top speed bar to a maximum of 140 mph. Followed the success of the CBR600 F2, Honda released the CBR600 F3 in 1995, the fourth in the series. The model had a Dual-Stage Ram Air system with an even higher compression ratio and a computer-controlled 3D-mapped ignition system. The radically designed CBR600 F4, push the limits of performances delivered by the 600 cc class of engines even higher. The new engine utilized RC45'„¢ aluminum composite cylinder sleeves and LUB'„¢ coated pistons in the inline-four, delivering over a 110 BHP. The chassis is manufactured entirely out of an Aluminum Pro Frame'„¢, making it 15.4 pounds lighter, weighing only 372.6 pounds. The newer Honda Multi-Action Suspension'„¢ (HMAS) system and the wider three-spoke wheels with low profile radial tires boosted the already exceptional handling capabilities to newer heights. It was launched in 1999. Models, later launched in the series, with similar upgrades and enhanced performance are the CBR600F4i in 2001 and the CBR600RR in 2003.