2009 Yamaha R1 v Aprilia RSV4 on the dyno

Same day, same dyno - with surprising results

THE APRILIA RSV4 and Yamaha YZF-R1 are two of the most talked-about superbikes of 2009.

Ben Spies and Max Biaggi took both bikes to glory in this year's World Superbike series: Yamaha-riding Spies took the 2009 title, while Aprilia-mounted Biaggi took an impressive fourth in the overall standings, in the RSV's first year of competition.

But check the graph above, found on the Aprilia Forum, which show dyno figures for both bog-standard road bikes, taken on the same day on the same dyno. The blue line is the Aprilia, red is Yamaha.

The Aprilia's max power is listed at 162.5bhp at the rear wheel, while the Yamaha cranks out over 3bhp less at 159bhp.

But also look at how the Aprilia continues to make power all the way to 13,000rpm, while the Yamaha starts to tail off sharply 1,000 revs earlier.

The torque curves in the second graph show the Yamaha ahead through the majority of the run, but it's a close thing.