Yamaha's R1 has been tweaked and massaged for 2006 to produce a claimed 2.2kW more power at 12 500rpm. To give you an idea of the detail work this involves, the intake valve guides have been shortened by 5mm to 27.5mm.
This allows a smoother, straighter intake port and improves intake gas flow; Yamaha says it also reduces frictional losses on the valve stems but I somehow doubt the difference would be measurable.
The cam chain tensioner has been revised and the clutch boss modified for better oil flow to the clutch assembly.
Its chassis has also been nipped and tucked to move the weight bias one percent further forward and extend the swing-arm by 20mm; the frame thickness has been modified to change the frame rigidity balance without affecting vertical rigidity
Only 500 R1 SPs will be produced to legalise its special suspension, wheels and slipper clutch
The front suspension has been modified to suit the revised weight bias, including a new lower triple clamp. The rear engine mounts have also been revised and the swing-arm pivot has been moved to optimise the effect of its increased length on the handling – but that's not the big news.
The big news is that for the first time on a Japanese litre-class sports bike Yamaha has seen fit to build, alongside the standard model, a limited-edition "SP" (sport performance) version dripping with the special components American journalists used to call unobtanium because you just couldn't get them in the US.
SPs are generally low-volume, homologation specials, sold to the public in just sufficient numbers to satisfy racing regulations
Each of the 500 R1 SP's will have a small plaque engraved with its production number to underline its exclusivity
The slipper clutch does exactly that – it slips under hard engine braking to reduce rear wheel chatter and uncontrolled slides. It also makes possible hair-raising clutchless down-changes without upsetting either gearbox or chassis composure.
Apart from the special clutch, the engine is standard but the running gear is really special, based on world-class components from Swedish suspension specialist Öhlins, carefully set up to match the R1's chassis characteristics and tuneable through a wider range of adjustment than the unit on the "ordinary" version – believe me, there's nothing ordinary about any R1!
The rear suspension has a hydraulic pre-load adjuster that allows quick and accurate settings "on the fly" as well as a compact ride height adjuster in a relay arm on the suspension linkage. This allows your pit crew to raise or lower the rear ride height without affecting the spring preload or static sag settings.
The 43mm Öhlins upside-down forks have a TiN coating on the chrome sliders to minimise stiction while the outer tubes are also anodised gold. They're adjustable for preload, compression and rebound damping through a greater range of parameters than the "standard" units.
By far the most eye-catching special components on the SP, however, are the Marchesini forged aluminium rims, with the same Y-shaped spokes as used on Valentino Rossi's M1 MotoGP machine.
Each is 400g lighter than a cast rim of equivalent strength which Yamaha says is responsible for the R1 SP's superior handling and road-holding, together with the revised rigidity balance of the frame.
The R1 SP will only be available in a distinctive colour called Gun Smoke, with gold wheels, gold anodised underseat silencers and and a special gold-coloured Triple Tuning Fork badge on the fuel tank.
Each of the 500 R1 SP's will have a small plaque engraved with its production number to underline its exclusivity.
The standard 2006 R1 with chassis and engine updates is already available in South Africa at R113 000. The R1 SP version should be here in late February or early March – as always Yamaha is not prepared to quote prices until they arrive.
Specifications (standard R1):
Motor: Liquid-cooled four-stroke transverse four.
Bore x stroke: 77 x 53.6mm.
Compression ratio: 12.4:1.
Valvegear: DOHC with five overhead valves per cylinder.
Power: 128.7kW at 12 500rpm.
Torque: 106.6Nm at 10 500rpm.
Induction: Electronic fuel-injection with four throttle bodies and motor-driven secondary valves.
Ignition: TCI (digital).
Clutch: Cable-operated multiplate wet clutch.
Transmission: Six-speed constant-mesh gearbox with final drive by chain.
Suspension: 43mm inverted cartridge forks adjustable for preload, compression and rebound damping at front, monoshock adjustable for preload, compression and rebound and ride height damping at rear.
Brakes: Dual 320mm disks with radial mount four-pot opposed piston Sumitomo callipers at front, 220mm disk with single-piston Nissin floating calliper at rear.
Tyres: Front: 120/70 -ZR17 tubeless. Rear: 190/50 - ZR17 tubeless.
Wheelbase: 1 415mm.
Seat height: 835mm.
Fuel capacity: 18 litres.
Dry weight: 174kg.
Price: R113 000.