Hard Parts
Don't dare call it a Yamaha
Despite bigger 90mm bores,...
Despite bigger 90mm bores, a tidy chain/gear cam-drive narrows included valve angle, making the 1679cc V-4 compact enough to move forward in the frame, putting more weight on the front wheel to optimize chassis balance.
Engine
Combustibles enter through a quartet of 48mm Mikuni throttle bodies and YCC-I variable-length velocity stacks: 150mm up to 6650 rpm and 54mm from there to the 9500-rpm redline. Despite bigger, 90mm ceramic-coated bores paired with the original-recipe 66mm stroke inside an integrated cylinder/crankcase casting, the new 1679cc eyeball-flattener is more compact where it counts: 27mm shorter across the heads and 7mm shorter overall. How? Chain-drive intake cams geared to exhaust cams allow a 29-degree included valve angle that keeps top-end dimensions tight and permits optimal placement in the frame. Cylinders are arrayed in a 65-degree angle, 5 degrees narrower than the 1198cc version that prowled the streets from 1985 to 2007. It takes 6.2 quarts of oil vs. 5.0 for the old 1198cc V-4. At 606mm, it's 6.5mm taller than before. Forged pistons and fracture-split carburized connecting rods spin the 180-degree crankshaft, while a single contra-rotating balance shaft squelches offending vibration. A 4-1-2-4 exhaust system-complete with torque-boosting EXUP valves, three-way catalytic converters and closed-loop oxygen sensors-turns noise into beautiful music. Cam covers are magnesium; muffler cans are titanium.
Electronics
Denso builds the brains for the beast: a 32-bit EFI CPU, integrated with a pair of processors that run the YCC-T fly-by-wire throttle system, all in one little black box. The computer samples ambient data from 15 separate sensors 1000 times every second to make the smartest fueling decisions and optimize throttle response. Data readout atop the faux fuel tank shows odometer and trip data, plus a fuel gauge, gear indicator, coolant temperature, fuel consumption, intake air temperature, throttle-valve angle, stopwatch and countdown timer. Using rows and columns of organic materials printed on polymer film, the compact electroluminescent display doesn't need to be backlit, so it's thinner and draws less current.
Drivetrain
There's enough torque to get by with a three-speed, but the new gearbox offers five cogs just the same. Goodbye,'85-spec diaphragm: The '09 gets a hydraulic ramp-type slipper clutch that's stronger and much better behaved, squeezing 19 plates with six coil springs. Shaft drive uses a dual cross-joint design and smaller final-drive cogs to make room for that phat 200mm-wide rear tire.
Six-piston radial-mount Sumitomo...
Six-piston radial-mount Sumitomo calipers and 320mm wave-type rotors trade initial bite for reassuringly linear feel. ABS is part of the equation, but never takes over prematurely.
Chassis
The twin-spar main frame is cast aluminum, varying wall thickness from 3 to 6mm. The bolt-on subframe combines aluminum die-castings and extrusions. The swingarm is cast aluminum as well, carrying a rising-rate linkage that bolts to the top of the diagonally mounted rear shock.
Wheels And Brakes
Cast-aluminum five-spoke wheels are news at both ends. The 3.5 x 18-inch front carries wave-type 320mm rotors grasped by radial-mount six-piston Sumitomo calipers, cued by a Brembo radial master cylinder. A single-piston Akebono caliper and 298mm wave rotor handle rear braking chores. Bridgestone BT028 radial rubber was designed specifically for Mad Max.
Suspension
A titanium-oxide coating on those 52mm fork tubes cuts nasty stiction. They live 225mm apart in aluminum triple clamps-the upper cast, the lower forged-with 30mm of offset. The sliders are extruded aluminum, while the axle carrier is cast aluminum. The Soqi fork is adjustable for spring preload, compression and rebound damping, as is the Soqi shock. Remote adjusters make dialing-in the rear suspension a blissfully tool-free experience.