YZR-M1(0WS4)

This was the first 800cc YZR-M1. The engine development focused on measures to accommodate the smaller displacement and a reduced fuel tank capacity limit of 21 liters dictated by the regulation changes. Compared to the 2006 model, the engine size was reduced by 8mm in width, 18mm in height and 5mm between axes, while the weight was reduced by 3.5 kg. However, there was still an approximately 3-5% decrease in top speed. To increase power output, new specs were brought out seven times during the course of the season. The end result was a 4% increase in power output and a 1,000rpm increase in revs, while fuel economy was improved by 3%. The basic policy with regard to the chassis was to maintain current performance levels, but a new cowl design and front fork were introduced for round six at Mugello. Further revisions were made in the cowl by round 12 that reduced front-end air resistance by 7%. The total effect of these improvements was a 3-10 km/h improvement in cornering speed, deeper braking points, and despite the decrease in top speed resulting from the reduced displacement, the actual lap times now roughly equaled those of the 2006 machine.

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