Exhaust manufacturer Akrapovic has revealed the power of the new Yamaha R1 in standard form is 161bhp at the back wheel.
The power figure was discovered as the Slovenian firm became the first to the market with a slip-on exhaust system.
With the exhaust system in place, peak power on the Yamaha R1 was raised to 164bhp. A pair of slip-on silencers with removable baffles cost £889. An optional link pipe which removes the catalytic converter is £296.
Check out the dyno chart and associated press release here