FEATURES: Revised ultra-compact. light-weight. brief stroke. 599cc. DOHC. 16-valve. liquid-cooled. in-line four-cylinder with light-weight titanium valves produces extraordinary horse power for a 600cc engine. Redline is set at a fantastic 16.000 rpm. The compression ratio has been increased from 12.8:1 to 13.1:1. 67mm bore and 42.5 mm stroke supply a quick revving powerplant. Engine width is reduced thanks to Yamaha's unique casting innovations and liner less cylinder design. Compact pent roofing cylinder head design includes ultra light-weight titanium valves for both consumption and exhaust. The consumption valve angle is 11.5 degrees and the exhaust is 12.25 degress. The intake valves are 27mm in diameter while the exhaust valves are 23mm. Single intake valve springs lower weight and friction for optimum high rpm performance. The valve spring material for both the consumption and exhaust has actually been modify ...