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 Wayne Rainey's 1987 OW86
OW86 (1987)- Yamaha's fourth manufacturers title
To accommodate the new noise regulation went into
effect in the GP from the 1987 season, changes were made in the exhaust system, including a lengthening of the tail pipe to reduce the noise level from 110 to 105 decibels. At the same time, the
maturation of the model continued with improvements like a revised engine position, increased radiator capacity and improved cooling performance with an expansion of the air duct. The power output was
also boosted from over 145PS to over 148PS. This year (1987) the first 500cc class Japan round of the World GP at the Suzuka circuit and Randy Mamola won it in the rain on the OW86. That season Lawson
won six rounds and Mamola three to give Yamaha its fourth manufacturers championship.
 OW98 (1988)- Right-side twin mufflers
On the OW98 that made its appearance in 1988 the V bank was opened
from 60 to 70 degrees. This change was made to gain more area for the reed valve itself and more space to increase intake volume than the original V4 block which had been designed for the rotary disc
intake system. Also, a new exhaust layout was adopted in which the exhaust pipes from the lower (front) two cylinders were crossed once under the engine and then both brought out on the right rear side.
To accommodate this, a left-right asymmetrical rear arm with a large curve on the upper right side was adopted.
This year, Lawson won seven rounds of the GP500 series to claim his third title.
Kevin Magee and Wayne Rainey also won one round each on the YZR500 to give Yamaha its third consecutive and fifth overall manufacturers title. In the twelfth round of the series at Donington Park,
Rainey won on a YZR500 after adopting a carbon front disc brake for the first time.
 OWA8 (1989) - Data-recording device introduced
The OWA8 that appeared in 1989 was characterized by the
introduction of a full-fledged data recording function that recorded data from sensors about the running conditions of the machine throughout the duration of its run. With its ability to record data
about a wide range of factors including engine rpm, bike speed, suspension stroke, steering angle during turns, combustion chamber temperature and detonation, this machine proved to be extremely helpful
in providing numerical information that could be shared by the engineers, mechanics, developers and riders to help in determining directions for settings. This year Lawson scored three wins to finish
the season in second place, followed by Christian Sarron in third. Meanwhile, in the All Japan Championships, Norihiko Fujiwara grabbed his third consecutive season title on this machine.
 OWC1
(1990) - Rainey wins world title
The OWC1 spec that Yamaha rolled out in 1990 had improved handling stability due to dimension changes including a head pipe position that was closer to the rider than
the conventional machine and a lower caster angle. The power output was also increased to 155PS from 150PS for the previous year's model. On this machine Rainey won a total of seven rounds to claim his
first GP title. This contributed to Yamaha's sixth manufactures championship. This OWC1 would also be the base machine that Yamaha would offer to European constructors in 1992 in the form of engine
sales and chassis data as a move to stimulate the sport of motorcycle racing and encourage technology sharing. This would lead to Harris Yamaha and ROC Yamaha entering machines based on the OWC1.
 OWD3 (1991)- The machine Rainey rode to title two
Due in part to the new regulation that required 500s to weigh more than 130 kg, the OWD3 spec introduced in 1991 sought to increase
competitiveness with the adoption of an electronic-control suspension (CES). It also adopted a full-fledged adjustable pivot assembly designed to hold the influence of return force from the road surface
on the chain tension to a minimum while also enabling setting adjustments to accommodate different course conditions. Rainey won six rounds of the '91 series on this machine to claim his second world
title. John Kocinski also won one round to help bring Yamaha its seventh manufacturers title. This OWD3 was also ridden to a series title in the All Japan Championships by Peter Goddard. This gave
Yamaha the greatest number of titles of any maker in the 13-year history (1981-1993) of the All Japan 500cc class with eight.
 OWE0 (1992) - Rainey's third title
The OWE0 that appeared in 1992
boasted a power output of 160PS, up from 155PS the year before. Also, based on the premise that torque character is the product of a combination of combustion torque and inertial torque from the
revolution of the crankshaft, a new phased simultaneous combustion interval (the diagonally opposed cylinders fired simultaneously at a 0-degree and 90-degree interval as opposed to the previous
180-degree interval) was adopted from the ninth round of this year's series, the Hungary GP. This improved traction in the low- to mid-speed range and power coming out of the turns. On this machine
Rainey won his third title in as many years. Kocinski also scored one win and finished the season in third place.
 Rainey's OWF2 of 1993
OWF2 (1993)- Adopting an extruded aluminium frame
In order to accommodate a new engine with boosted power output of 170PS (160PS for the previous year), the OWF2 that Yamaha rolled out in 1993 featured a frame designed for greater rigidity. The
aluminium used in main frame was changed from three-section extruded stock that provided much greater rigidity, especially with regards to lateral torsion. Rainey rode this machine from the opening round
of the '93 series to round seven, the Dutch GP, scoring wins in the Malaysia GP and the Japan GP and contributing to Yamaha's eighth manufacturers title. From round eight, Rainey rode a ROC Yamaha
machine (with the same type of frame as the OWC1) constructed in Europe with Yamaha technological assistance.
 OWF9 (1994-95) - Forced air box boosts performance
The 1994 model OWF9 was the
machine that Luca Cadalora rode throughout that year's GP series to second place for the season with wins at the U.S. GP and the Barcelona GP. While the OWF2 spec of the previous year had featured an
extruded aluminium frame, further pursuit of power development and rigidity balance factors led to a return to a panel stock aluminium frame with this model. Based on development efforts to improve the
aerodynamic characteristics over preceding models led to a cowl design that shifted the air intake mouth toward the inside. Norick Abe became a full-time competitor on this machine starting from this
year's British GP.
A further matured version of the OWF9 was also used in the '95 season, characterized by features like a full-fledged ram-air function for the air box produced at Yamaha's
London R&D base, Activa, that increased intake performance.
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