2009 Yamahas YZF-R1 And FZ6R
Yamaha hosted its annual dealer meeting in Las Vegas this past September, introducing two new sportbike models along with the Star V-Max featured elsewhere in this issue. Of note to sportbike riders are an all-new entry-level middleweight-the FZ6R-and a revised YZF-R1. We had been anticipating an updated R1, but the scope of the changes is much broader than we expected and include some interesting MotoGP trickle-down technology.
YZF-R1
While the company's flagship sportbike was heavily updated in '07, Yamaha has further revamped the R1 for '09. The highlight is the use of a "crossplane" crankshaft that spaces the journals at 90-degree intervals as opposed to the traditional 180, giving the engine an uneven firing order. The design is based on experience from the M1 MotoGP program and is said to provide a "more linear driving force in response to throttle movements and more linear controllability when exiting a corner for maximum acceleration."
In a typical engine, vibration is caused by the piston moving up and down, accelerating and decelerating with every stroke. Counterweights on the crankshaft are used to offset some of the weight of the piston, ring and connecting rod assembly, but this simply transforms some of the up/down inertia to a fore/aft direction as the crankshaft spins. Multi-cylinder engines allow each cylinder's inertia to be offset with another's; for example, in an in-line twin-cylinder engine, the rising piston nicely offsets the falling piston, eliminating primary vibrations-those acting at crankshaft speed. Because the cylinders are separated, however, a rocking couple is created. A four-cylinder engine with a conventional crankshaft eliminates that rocking couple because each set of rocking pistons is offset by the second set. There are still secondary vibrations and moments-those acting at twice crankshaft speed-present in a conventionally laid out four-cylinder engine, and these are sometimes dealt with by a small shaft rotating at twice crank speed.
 The new R1 keeps the old model's YCC-T and YCC-I, but the lengths of the adjustable stacks are substantially different from previously and they are actuated at 9400 rpm, 1000rpm lower than before. The ride-by-wire mapping can be altered by a drive-mode switch, offering a choice of three modes. Showerhead-style secondary injectors, mounted inside the airbox lid, have been added. |  The R1's crossplane crank spaces each cylinder 90 degrees from the next. This layout gives perfect primary and secondary balance, but a counter rotating shaft is required to offset a primary rocking couple. A conventional 180-degree spacing has no primary rocking couple but is not balanced for secondary vibrations, hence the need on some bikes for a balance shaft spinning at twice crankshaft speed. |
 A combination of castings and extrusions make up the R1's frame, with a cast front section mated to controlled-fill die-cast outer frame rails and extruded inner rails. The front engine mount is now on the bottom front of the cylinder head, necessitating very long frame extension and changing the engine's contribution to chassis stiffness. |
Yamaha's crossplane crankshaft, with each journal offset by 90 degrees, retains the conventional layout's perfect primary balance but nicely eliminates the secondary vibrations, smoothing what Yamaha refers to as inertial torque. However, a new primary rocking couple is introduced, and this must be offset with a shaft rotating opposite to the crankshaft and at the same speed. An interesting side-benefit of the crossplane crankshaft can be seen in the R1's unevenly shaped counterweights. For each cylinder the weight farther from the center of the crankshaft is larger than the one closer, and the weights for the outer two cylinders are significantly smaller than the inboard cylinders' weights. A European patent applied for by Yamaha's Executive Officer of Engineering Operations Masao Furusawa indicates that the crossplane crankshaft uses smaller than typical counterweights-in other words, less of the piston assembly's up/down inertia is translated to fore/aft inertia. This makes the crankshaft lighter but introduces a primary imbalance. Conveniently, by using a precise weight ratio between each cylinder's counterweights this imbalance can be offset by the balance shaft already in use to offset the primary rocking couple-an interesting and elegant optimization of the overall layout.
Other updates inside the engine include a 1mm-larger bore and correspondingly shorter stroke to retain 998cc of displacement. A three-position drive-mode switch on the right clip-on controls the YCC-T mapping and allows the selection of modes for optimum overall performance (standard), more emphasis on low- and mid-range acceleration (A) or less sharp response (B).
 Dual projector-beam headlights replace the R1's previous four-light arrangement, with the ram-air ducts now positioned in the previous high-beam location. |  Even with the addition of a counterbalancer, the R1's engine is still quite compact. |
 The crossplane crankshaft results in an uneven firing order, which Yamaha says gives the R1 both the low-rpm torque of a twin and the high-revving horsepower of a four-cylinder. |
The new engine is housed in a frame constructed of a mix of castings and extrusions, with a cast magnesium subframe and a swingarm with revised rigidity balance. The front brakes appear similar to last year's, while a Soqi fork replaces the old bike's Kayaba unit and now has compression damping in one leg and rebound in the other-said to improve performance by dedicating each leg to a single task. The rear shock retains both high- and low-speed compression damping adjustments (in addition to rebound), but preload is now adjusted hydraulically. The shock's linkage has been reversed, with the dogbone attached to the swingarm, lowering the shock and freeing up room under the seat and tank. The rear tire is now a larger 190/55 size, and U.S.-bound R1s will be Dunlop-shod. The press material indicates the steering damper is now electronic or electronically actuated, with no other details. Adjustable rearsets allow the footpeg position to be moved 15mm up and slightly rearward of the standard position.
The new R1 will be available in January with four color options and a list price of $12,390-$12,490. We'll have more information-and a first-ride report-in an upcoming issue.
FZ6R
Yamaha's other new model for 2009 is the FZ6R, an entry-level middleweight that differs significantly from the FZ6, which stays in the company lineup. While the powerplant appears to be the same previous-generation R6 unit, the cylinder head, crankcase, intake and exhaust systems and clutch have all been redesigned, "creating a power unit with an entirely new character." The R's steel-tube frame-as opposed to the FZ6's bolt-together aluminum unit-helps make the midsection slimmer to complement the bike's low seat height, which can be raised 20mm from the standard position. The handlebar can also be adjusted 20mm forward of its as-delivered setting.
Other major differences to the FZ6 include a full fairing and the switch from underseat exhaust to an underengine unit. The FZ6R's running gear appears to be somewhat downgraded, with smaller fork tubes, a 160mm-wide rear tire (as opposed to a 180), two-piston, slide-pin calipers up front replacing the FZ6 four-pot monoblock units and a plain steel swingarm used in lieu of an extruded aluminum unit. This helps to keep the bike between $200 and $300 cheaper than the FZ6, and the FZ6R should provide some interesting competition for the Suzuki GSX650F and Kawasaki Ninja 650R.
The FZ6R is offered in team Yamaha blue/white, raven, pearl white and cadmium yellow color schemes. List price is $6990 for the raven model and $7090 for the other colors, and the bike will be in dealers in January of next year.
The Others
One year after its own makeover, the YZF-R6 should benefit from minor tweaks to its YCC-T system that improve midrange power and drivability at a small expense to top-end. The FJR1300A receives an updated clutch to reduce lever effort, while the AE model's YCC-S electric shifting system is remapped to improve response. The YZF-R6S, FZ1 and FZ6 all return unchanged aside from color options and graphics.
Source --> sportrider.com
No comments:
Post a Comment