MOTOGP INSPIRATION
FOR NEW YAMAHA R1

Yamaha is celebrating the start of its second decade of YZF-R1 production with a completely new motorcycle for the 2009 model year. At a dealer show at the Mirage in Las Vegas on September 8, the company’s entire MotoGP rider line-up – Valentino Rossi, Jorge Lorenzo, Colin Edwards and James Toseland – presented the new bike and when Edwards fired up the engine, it was immediately obvious there had been some big changes. The new engine sounded similar to the YZR-M1 race bike, although with road-legal mufflers, more subdued. However, unlike the YZR-M1 MotoGP bike’s exhaust placement, the R1’s pipes are still placed about as far up and back from the centre of mass as possible. Yamaha says it went for the ‘up pipes’ so it did not have to compromise the design of the rear suspension linkage and swing-arm. Word is they tried to design an R6-type exhaust system but it wouldn’t fit properly without upsetting the design of the rear suspension and swing-arm.

RADICAL NEW CRANK

The exhaust note is not the typical wail of an in-line four. It sounds much more like a mid-1980s Honda V4 racer. Which makes sense as Yamaha has revealed the new R1 uses what it calls a ‘crossplane crankshaft.’ Simply put, the new crankshaft has its crank-pins set at regular 90° intervals. So, when piston number 1 is at top dead centre (TDC), number 2 is at 90° before TDC, number 3 is at bottom dead centre (BDC) and number 4 is at 90° before BDC. This results in uneven cylinder firing intervals: 270° - 180° - 90° - 180° – exactly the same as a 90° V4 with both crankpins set at 360°. A typical in-line four with a flat plane crank (two up, two down) fires its cylinders at regular 180° intervals, which is what gives this design its familiar wailing sound at high rpm. Anyone who has heard the MotoGP Yamahas (both the later 990s and the recent 800s) will have noted their off-beat sound, which sounds just like a Honda RC30 V4. Now we know why.

RACING PEDIGREE

Back in the 1970s when Yamaha was racing two-stroke parallel twins, and selling a similar design of road-going machine, its slogan was ‘racing improves the breed.’ It has been a while, but finally MotoGP technology has been crossfertilised into Yamaha’s road bikes. So from early 2009 you will be able to buy an in-line four that sounds just like a V4. This is the third major change for the R1 engine since its conception in 1998. The first was in 2004 when Yamaha produced a completely new engine, then in 2007 it abandoned the five valves per cylinder design – a layout it had used in its top-line sports bikes from the time it released the FZ750 in 1985 – and switched to four valves a cylinder. The four valve combustion chambers have been retained in the new bike, along with the electronically controlled variablelength intake funnel system (now with a secondary fuel injector atop the intake funnels), the electronically controlled throttle system and the slipper-type clutch to prevent rear wheel hop when rapidly shifting down the gears. When engine speed exceeds 9400 rpm, a servomotor separates the upper funnel from the lower intake funnel to allow a shorter intake and enhance intake air flow. The electronic trickery continues in the throttle control. There’s no throttle cable. The twist grip sends an electronic signal to the engine control unit which adjusts throttle butterfl y opening in 1/100th of a second intervals. For 2009, Yamaha has followed the lead established by Suzuki with its adjustable engine mapping. In Yamaha’s case, there is a standard setting or the rider can select A-mode for sharper engine response, or B-mode for more gentle response to throttle inputs (a wet weather setting, perhaps?).

SHORTER STROKE

The 2007-‘08 R1 already had a shortstroke engine, with a bore of 77mm allied with a piston stroke of 53.6mm. For 2009, Yamaha has increased the cylinder bores to 78mm and reduced the stroke to 52.2mm, which means the engine can be revved higher with safety. Engine displacement is now 998cc with peak power of 182 PS (180 previously) developed at 12,500 rpm while peak torque of 115.5 Nm (112.7) is developed at 10,000 rpm. Yamaha has retained forged aluminium alloy pistons for the R1, and the cylinder bores are ceramic-composite coated to improve heat dissipation. The cylinder block is of the closeddeck design with no coolant passages passing from the cylinder to the cylinder head. This means there is more metal-to-metal contact at the cylinder head gasket surface, which Yamaha says makes for more reliability in a high (12.7:1) compression engine. In another change, the all-new crankshaft now spins on 36 mm main bearing journals, up from the 32mm mains used in the 2007-’08 models. To help the new engine breathe at the high rpm it is capable of, Yamaha has redesigned the air intake system, with air gathered up by ducts in the nose of the fairing and fed through the frame side rails (same as the 2007-’08 models) to the airbox. On the other side of the combustion chambers is an all-new titanium exhaust system which mates the pipes from cylinders one and four and those of cylinders two and three in a new 4-2-1-2 layout, with the mufflers exiting under the seat.

NEW CHASSIS

As Pirelli loves to point out, power is nothing without control. So for 2009 Yamaha has come up with a completely new chassis for the R1. There is a new frame that uses different types of aluminium for sections such as the steering head, engine mounts and swing-arm pivot (gravity cast), the main spars (combination of CF die-cast and extrusions) while the seat supporting sub-frame is made from magnesium alloy (first used on the 2008 YZF-R6). The swing-arm is made of a gravity case pivot section and twin arms make use of Yamaha’s controlled filling (CF) die casting technology developed in 2002. The engine is mounted 12mm further forward in this frame and is an integral part of the structure. There are four rear engine mounting points and two on the cylinder head (one each side). Yamaha has learned from its MotoGP experience and has placed the swing-arm pivot a few millimetres lower than previously and as close to the gearbox output sprocket as possible. This change in vital rear-end geometry is designed to minimise rearend squat under hard acceleration out of corners. Using an idea Italian suspension manufacturer Marzocchi used in the late 1980s with its M1-R forks (and more recently by Suzuki with its MotoGP machines), Yamaha has adopted SOQI front forks which use independent damping. The left fork handles compression damping and the right side handles rebound damping. Yamaha sees this as a benefit. Separating the damping functions, the company says, offers a number of advantages, including simplifying damper valve design and oil flows, easier adjustment and reduction of cavitation (leading to frothing of the damper fluid during successive suspension strokes), and the ability to use different viscosity damper fluids to fine tune damping. What is SOQI? It is a wholly owned Japan-based subsidiary of Yamaha Motor Co., Ltd., in other words a Yamahaowned suspension company. (Yamaha used to own the Swedish suspension specialist company Öhlins until in December 2007 founder Kenth Öhlin bought 95% of the company back after a 25-year-long, prosperous cooperation with Yamaha). “Separating the damping function has also enabled our engineers to increase the diameter of the internal cylinders which helps stabilise pressure variations,” Yamaha says, explaining the new forks. “This increase in (damper) cylinder diameter and oil volume also ensures there is always sufficient oil available to deliver effective damping force for even the smallest amount of front suspension movement,” Yamaha says. Rear suspension is handled by a SOQI shock that features separate adjustment for high and low speed compression dam ping, adjustable rebound damping and hydraulic adjustment of rear spring pre-load. Talking about adjustability, Yamaha has made the footrests adjustable in two positions, with the standard, lower position aimed at taller riders looking for a more ‘open’ ergonomics. The high position raises the pegs 15mm up and at the same time setting them 3mm further back, designed to provide additional ground clearance for more aggressive riding. After spending so much time on the chassis and suspension, Yamaha also looked at the profile of the rear tyre, and opted to switch to something with a little more sidewall. Thus, the rear tyre is now a 190/55 x 17 (190/50 x 17 previously).

AGGRESSIVE NEW LOOK

In addition to the engine and chassis changes, Yamaha has fitted the YZF-R1 with a brand new set of plastic work. One of the more interesting moves, and something that sets the new bike apart from previous incarnations, is the new twin headlight set-up. In place of the four projector lights used on the 2007-’08 model, Yamaha has fitted twin projector beams and from what we can gather from Yamaha, these lights are on high beam all the time. To ‘dip’ the lights, a shade covers part of each light, operated by a solenoid coil type high/low beam switching mechanism. There is no longer a clear plastic cowl covering the lights. Instead, the dual lights are exposed. This is because immediately outside of them are the intakes for the forced air intake system. Rounding out the updates to Yamaha’s flagship sports bike is a new instrument panel. This features a new multi-function meter panel incorporating a speedometer, tacho, coolant temperature indicator, intake air temperature indicator, twin trip meters, fuel meter, clock, stopwatch gear change timing light, gear position indicator and engine mode indicator. At this stage it is expected the all-new YZF-R1 will hit New Zealand dealers’ show rooms in late February 2009

KR