Cologne, Germany - At first glance Yamaha's 2007 R1 sport flagship looks like a mild facelift of the previous model, but look more closely...
Yamaha claims subtle changes to the shape of the upper fairing have improved the bike's aerodynamics and intake flow into the ram-air system while a layered lower section draws hot air away from the engine compartment.
But the big news is inside the engine; Yamaha has abandoned its trademark five-valve cylinder head in favour of a more conventional four-valve layout - but with titanium intake valves - and the compression ratio is up from 12.5 to 12.7:1.
The new fuel-injection system has what Yamaha has dubbed chip-controlled intake; it's long been known that a longer intake boosts bottom-end power while a shorter throat makes more power at high revs.
The YCCI system uses a little computer-controlled electric motor to move the throttle bodies in and out; intake tract length is 140mm at low revs, reducing to 65mm at peak revs; Yamaha says this spreads torque and horsepower over a broader range than with a conventional fixed-lengh manifold.
The R1 now has a "fly-by-wire" electronic throttle similar to that on the 2006 R6, driven by a mini-computer that reads throttle position every 0.001sec, while the ramp-type slipper clutch fitted to the limited-edition 2006 R1-SP is now standard equipment.
R1's have always had overheating problems when ridden hard (hence the layered fairing) so, for 2007, the radiator's capacity has been increased by 13 percent.
The R1 also gets a new exhaust system (all titanium except for a stainless-steel midsection and catalyser) to take advantage of the engine's improved breathing; the result is a claimed power increase across the board (bottom end, mid-range and top-end power), with peak output up 3.5kW to 132kW at the crankshaft.
The cast-alloy frame has been revised ("flex-tuned" in Yamahaspeak), the new swing-arm is 30 percent stiffer torsionally and slightly less stiff laterally, and the swing-arm pivot is 3mm higher than before; Yamaha claims improved turn-in and better traction, hard on the power coming out of corners.
The new 43mm upside-downies have larger pistons (up from 20mm to 24) while Yamaha says their rigidity is tuned to that of the new frame for better handling.
The 310mm front disc brakes have new six-piston, radial-mount brake callipers by Sumitomo that grip the disc closer to its edge, effectively making the swept area - and thus braking force - as big as that of the previous model with its bigger, heavier discs
Expect to see the new R1 in South Africa in March 2007; prices, as always, then.