The Yamaha YZF-R1, or simply R1, is a -class sports motorcycle made by Yamaha. It was first released in 1998, undergoing significant updates in 2000, 2002, 2004, 2006, 2007, 2009, 2015, 2018 and 2020. 1998–1999 Yamaha launched the YZF-R1 in 1998 after redesigning the Genesis engine to create a more compact engine by raising the gearbox input shaft and allowing the gearbox output shaft to be placed beneath it. This "stacked gearbox" was followed by other manufacturers. Compacting the engine made it much shorter, allowing the wheelbase to be shortened as well and the center of gravity to be optimized. The swingarm could be made longer without compromising the overall wheelbase, which was a short . Four 40 mm Keihin CV carburetors fed fuel to the engine. The R1 was also equipped with a 41 mm KYB upside-down front fork and 300 mm semi-floating disc brakes. The instrument panel was electronic, with a self diagnosis system and digital speed readout. The exhaust used Yamaha's Exhaust Ultimate Power Valve (EXUP) system, which controlled exhaust gas flow to maximize engine power production at all revs, resulting in a high-power and high-torque engine. The Yamaha YZF-R6 was introduced in 1999 as the 600 cc version of the R1 super bike. The 1999 R1 saw only minor changes, apart from paint and graphics. Improvements included a redesigned gear change linkage and an increase in gear change shaft length. Fuel tank reserve capacity was reduced from , while total fuel tank capacity was unchanged at . Motorcycle Consumer News tests of the 1998 model year YZF-R1 yielded a time of 2.96 seconds and of 5.93 seconds, a time of 10.19 seconds at , and a top speed of , with deceleration from of . For the 1999 model year, Cycle World tests recorded a time of 3.0 seconds, time of 10.31 seconds at , and a top speed of . 2000–2001 In 2000, Yamaha introduced a series of changes to improve the R1, and minor changes to the bodywork to allow for better long-duration ride handling. Yamaha's main design goal was to sharpen the pre-existing bike and not to redesign it. The dry weight was reduced five pounds to . At at the rear wheel, top-end output remained the same, but changes to the engine management system were intended to result in a smoother, broader distribution of power. The bodywork remained similar to that of