Cycle News - Archive Issues - 2000's

2003 Yamaha YZF-R6 who, like I did, had to stick a steering Tile .\\••' ••r HII.I tHller TIIIII s Til;.' S .111 A lot has been changed on the motor and its ancillary components for 2003, so let's start where it starts - the ram-air intake. The ram-air inlet on the front of the fairing may look different, but it's the same size and feeds the new 7.6-liter airbox, which was increased from 7.3 liters. Not only is the airbox larger, but it is also less restrictive internally. The air mixture then feeds into the throttle bodies on the new EFI (electronic fuel injection) system, which is new for 2003. The throttle bodies are 38mm units that feature diaphragm slides similar to a CV (constant velocity) carb's vacuum slides. This simplistic design is the key to making the R6's (and Rl's) throttle response so smooth. The CVtype slide helps control the airflow mechanically, as opposed to a computer trying to tell a secondary butterfly what it should be doing. The fuel is then forced into the combustion chamber at 41.2 psi. The cylinder heads have various improvements for 2003, but nothing major. The intake cam now has more lift, which was increased from 7.8to 8.2mm for better acceleration, while the exhaust cams remain unchanged, but the cam-chain tensioner was redesigned for greater reliability. The valve cover is now made out of magnesium. which reduces the weight of the cover by 10 percent and also houses the air-induction valves. The only other change to the valvetrain is that the springs on the intake valves are new. The combustion chamber is exactly the same as on the old bike, but the cylinder-head gasket now has additional coolant passages for better efficiency. The pistons have been redesigned for improved power and efficiency. The piston skirt is thicker on the intake side; the top ring is now thicker; the piston pin is a new tapered design; the rod bearings are new, and new angle-tightening-type bolts are used, which require that you torque the bolt to a specific setting and then tum the bolt another 150 degrees. Sounds funny. but this is supposed to be more accurate for bolt stretch, otherwise the rods are the same as last year's. The crankshaft is completely new for 2003 - not only was the shape changed to improve its balance, but the weight was reduced by 5.3 oz - this helps to reduce stress on the bearings by 20 percent. The cylinders no longer have aluminum liners in them and now feature a ceramiccomposite coating applied directly to the cylinder walls. Not only is this supposed to improve heat dissipation, but it is supposed to help reduce oil consumption as well by improving the cylinder wall's roundness. The transmission has minor changes this year, including new pinion and wheel gears for third and fourth gears for better durability, while the axle splines for fifth and sixth gears have been modified for better shifting. The engagement dogs on second gear (which is also sixth) and fifth gear (which is also third) has been changed from three to five dogs for beller engagement. The shift cam has been improved as well for better shift action. The R6 has an all-new radiator, which is now a curved unit combined with a new ring-type fan to improve cooling efficiency. The fan was moved to the upper left side of the radiator where the hot coolant en route from the engine enters and causes a hot spot. The R6 features a new exhaust pipe with stainless-steel headers and canister but, to reduce weight, features titanium inner pipes and partitions - it is 2.2 pounds lighter and complies with U.S. and European emissions standards. 28 JANUARY 15, 2003' cue' e n e vv s damper on your old R6 right away. The bike is just as good as it that it was a street-compound tire on a racetrack. The R6 lets you know where its limitations are and allows always was in the big sweepers, you to trust the adhesion and just allOWing you to make corrections or worry about your lines. change lines effortlessly - like when The series of chicane-like, fast Mamola finally gets bored behind you right-left corners and the actual chi- and dives underneath. One of the cane require that the bike be flicked things that helped to improve this the like a switch, and the R6 is more than most happy to oblige. I never got tired on is the excellent throttle response, which doesn't unsettle the the R6 and was bummed that I bike in any way when you crack the throttle midcorner. It isn't as perfect couldn't stay out longer every time they threw the checkered flag to end as the R l's fuel injection, due either our session. The bike is as close to a to a hint of driveline lash, or maybe 250cc Grand Prix bike as production just to the lack of inertia from the four-strokes get. lighter crankshaft, but it's damned Another thing that I've always good. Another thing to bolster your liked about the R6 is its awesome confidence is the excellent feel from brakes - the new bike is no exception. the front end. I never felt anything The brakes aren't that different from other than perfect communication the previous bike's, but it does have from the front tire, despite the fact slightly changed rotors and new CDIhlm~~fi~o ~llJJ~IP)(eIID~fi®IID mIID® IB3®®~~:....::.-®-=-O ~IT]k=- _ Not only does the 2003 R6 look different, but the chassis has been completely changed from last year. The biggest change is to the frame itself, which is now a Deltabox III aluminum frame. Yamaha's new CF Die Casting process is a new process that has reduced the number of welds on the frame from 16 to 2. The subframe is now made from the same process and is much lighter and stronger than the old unit. It features steel bolts instead of the aluminum bolts that needed to be replaced if they were removed. The frame itself is now 50percent more rigid and is roughly as stiff as Yamaha's R7 unit. One of the key elements of the bike's chassis is the reduction in the distance between the center of the countershaft sprocket and the swingarm pivot by 10mm, which helps to improve the bike's traction under acceleration. The new swingarm in now manufactured with the same CF Die Casting process as the frame. which adds strength and keeps the weight in check. The swingarm is now 10mm longer, while the wheelbase is actually slightly shorter than last year's - 54.3 instead of 54.5mm. The front suspension features new 43mm Kayaba forks that are fully adjustable. The upper tubes are now thinner for less weight, while the spring ratio inside is changed as well for beller damping. The trail has been changed from 81 mm on the previous bike to 86mm on the new bike by moving the forks 5mm back in the triple clamps. As for the rear suspension, it features a new Soqi rear shock with provisions for ride height and is. of course, fully adjustable. The linkage plate is now aluminum instead of steel to save weight, while the spring rate itself has been changed. The rebound-damping knob has been changed from a knob to a screw-type adjuster. The brakes have been updated for 2003, with the front rotors getting a small redesign. The rotors themselves are the same, but the carriers now only have seven pins instead of 10, and only five mounting bolts to the wheel instead of six. The brake pads have a new sintered material, and the pads no longer require a backing plate to dissipate heat. The rear brake has been changed from a two-piston unit to a single-piston unit and the mounting points on the rotor have been changed from six points to five. The wheels are new as well and are now an attractive five-spoke design. The front wheel is 4-percent lighter to help improve handling and measures 3.5 x 17 inches while the rear measures 5.5 x 17 inches. U.S.-market bikes will come equipped with Dunlop's D208F tires. with a 120/60ZR17 on the front and a 180/55ZR17 on the rear. The bodywork on the new R6 is all-new for 2003, with many changes in both appearance and function. The biggest change is the new headlights, which are called gatlingbeam headlights. There is actually only one bulb for each pair of lights, which not only saves weight but is supposed to eliminate shadows and brighten illumination with less wattage. In the lowbeam setting, only the left two lights burn, and in the high-beam mode, all four come to life. The rear taillights feature LEDs like the previous model, but the new unit is 55- percent lighter. The turn signals are a new design and now are a much more attractive aerodynamic shape than the dated-looking units on the old bike. The bike receives the meter assembly that the R1 received last year, including the shift light at the top of the cluster.

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