YZR-M1(0WS8)

The aim of machine development for the 2009 M1 was to improve tire performance, drive power and fuel economy. Measures also had to be taken to accommodate the new regulations on the number of tires used per round and engines per season implemented from this season. Machine dimensions were reviewed from the standpoint of tire performance. The EMS functions were also revised toward the same purpose. To optimize front-rear weight distribution, the wheelbase was lengthened, the rider's center of gravity lowered and the riding position moved slightly forward. The longitudinal, lateral and torsional elements of the frame's rigidity balance were revised and changes were made in the shape of the frame to improve stability during braking and cornering. On the engine, the air box shape was revised, fuel pressure optimized, combustion chamber shape modified and friction loss reduced, all of which contributed to a 4% increase in peak power and 3% increase in max. torque. Furthermore, the revised combustion chamber shape contributed to a roughly 10% increase in the inertial mass of the crank at helped improve drivability. The optimized combustion chamber shape and improved cooling efficiency helped reduce the piston's running temperature enough to make the pistons last twice as long (cumulative running distance) without detrimental performance loss.

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