Yamaha's Masao Furusawa joined...
Yamaha's Masao Furusawa joined the company's motorcycle racing department at the same time as Rossi, and is considered as much a part of the M1's success as Valentino Rossi has been.
At the end of each MotoGP season, Yamaha has released a technical document detailing that year's M1 and its continued development. 2010, however, was the end of an era as Valentino Rossi has now left the company and Masao Furusawa, long considered the architect of the M1, is set to retire. To mark the occasion, Furusawa presented a historical presentation at the end of the year outlining key engine and chassis features of the seven M1 models Rossi had ridden.
The Rossi years - 2004 through 2010 - cover both 800cc and 1000cc versions of the M1, although each was an inline four-cylinder engine with a crossplane crankshaft and 16-valve cylinder head. As discussed in the historical document, the common theme of development over the seven-year stretch was not maximum power or ultimate handling, but rather to maximize the connection between rider and machine as well as to achieve a balanced package that excels in all conditions - including hot and cold, wet and dry, and at the beginning and end of a race. And as the rules changed over the years - encompassing the switch to 800cc, reduced fuel capacity, spec tires in limited quantities and maximum number of engines - development focused on maximizing the bike's performance within those rules. How was this accomplished over the seven years?
This timeline of the M1 shows how little the overall silhouette of the bike has changed over the past seven years. Two areas of interest: The fuel tank has gradually progressed downward and rearward, while the side vents in the fairing have changed significantly to improve cooling. The company is careful to improve aerodynamics without sacrificing yaw performance - how quickly the bike turns about a vertical axis.