Mounting a crossplane crankshaft, 4-valve engine
The development aims for the 2004 M1 were to achieve more linear throttle response while achieving both improved
handling performance and stability with a chassis layout better suited to the in-line-4 engine. Engine development focused on the by the crossplane crankshaft function (uneven firing interval) and further maturation of the idling control system ICS (idling control system) to achieve a natural engine brake effect. The combustion chamber was a new 4-valve type that was chosen for its potential to maximize the performance of the FI system. There was also further development of the EMS. While the previous year's model had performed on the basis of calculations from a pre-programmed control map, the OWP3 added to the mapped control a feedback type control system that reflected information on actual running conditions at any given time. The geometry of the frame was optimized with priority on stability. The rear arm was lengthened and the position of the engine was effectively moved forward. To help ensure stable suspension performance regardless of the changes in G forces coming to bear on the machine in the lateral direction during cornering, the relative rigidity in the lateral direction was reduced. This is the machine that V. Rossi rode to win his first MotoGP title with Yamaha.
- Capacity - 990cc
- Max Power - 240PS
1st: 9 Valentino Rossi Gauloises Fortuna Yamaha Team South Africa, Italy, Catalunya, The Netherlands, UK, Portugal, Malaysia, Australia, Valencia