The Yamaha YZF-R1, or simply R1, is a 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 the previous R1, although a 3% reduction in the drag coefficient was achieved. The headlight housing's profile was sharpened, the side panels were made more aerodynamic, and the windscreen was reshaped for better rider protection.
The seating area was also updated. The fuel tank was reshaped, with a more relaxed rear angle and deeper leg recesses to provide a better riding feel. The seat extended further towards the rear of the tank, and the new steeper seating position put additional weight on the front end. All of this was aimed at improving weight bias, thus offering sharper cornering and more stability.
Mechanically, the carburetors were re-jetted in an effort to improve throttle response, especially in the low end, all the way up to the bike's 11,750 rpm redline. The redesigned camshafts were lightened and used internal oil ways to lubricate journals that, when combined with reduced tappet clearance, provided less friction and created less engine noise. The gearbox received a taller first gear, a hollow chrome-moly gear change shaft with an additional bearing, and a completely redesigned shift linkage and foot pedal. These changes were aimed at eliminating problems with the transmission in earlier models, and to help seamlessly transfer the bike's power to the road.
2002–2003
A new fuel injection system was introduced for the 2002 year, which worked like a carburetor by employing a CV carburetor slide controlled by a vacuum created by the engine. With a similar power output to the 2000-2001 bike, though, the engine remained largely the same. One notable improvement was the use of new cylinder sleeves of a high silicon content alloy containing magnesium that minimized thermal distortion, reducing oil consumption. The exhaust system was changed from a 4-into-1 to a new titanium 4-into-2-into-1 design.