The 2009 Yamaha R1 boasts an all-new crossplane crankshaft engine that runs at an uneven firing interval. Watch this Yamaha promotional video for an explaination of the technology and reasoning behind their new 998cc powerplant.
The new engine design is said to give the bike a smoother and more linear throttle response.
Yamaha argue that this improves rider control and feel, creating a more direct connection between throttle hand and rear tyre. In a recent promotional video, Fiat Yamaha rider Valentino Rossi says that the new Yamaha R1 makes it "very easy to understand what's happening with the rear tyre under acceleration".