Service Motorcycle

All-new engine spins faster--11,450 rpm--and harder, churning out 56.3 bhp at 8500 rpm and 37.5 lb./ft. of torque at 7000 rpm.

Liquid-cooled four-valve Unicam® 449cc engine produces more than 125.3 hp per liter and now utilizes a four-lobe camshaft and individual rocker arms for each exhaust valve to reduce weight and contribute to higher rpm ceiling.

Engine completely redesigned to lower the overall height and position it closer to front wheel, resulting in a lower overall Cg and better weight distribution for better handling.

Engine height reduced by shortening length of connecting rod 3.5mm (105.6 to 102.1mm) to allow shorter cylinder.

Relocated crankshaft main journal cradles (inside of flywheels) allows reduction of connecting rod big-end diameter (34 to 33mm), reducing weight while maintaining overall strength.

Crankshaft cutaway eliminates piston skirt contact at BDC, also reducing weight.

Reshaped cylinder head combustion chamber is shorter yet has a larger volume squish area for better flame propagation.

Lightweight titanium intake valves and redesigned valve springs reduce overall engine height and permit higher rpm. New intake valve stem diameters reduced (5.5 to 5.0mm).

Lower camshaft mount built into the cylinder head to reduce weight and engine height.

Cam sprocket now press-fitted to camshaft, reducing weight by 20 grams compared to previous bolted design.

Cylinder attaches to engines cases with through-bolts instead of studs, allowing in-frame cylinder removal.

New forged slipper-piston material permits thinner crown, contributing to shorter cylinder height. Low-friction surface treatment assures high-rev potential.

Lightweight Ni-SiC cylinder lining provides cooler and quieter operation for extended engine life.
Redesigned, lighter auto decompression system and hot restart procedure is simplified with cam-integrated plunger and shaft-integrated decompression weight for easy starting in hot or cold conditions.

All-new Programmed Fuel Injection system (PGM-FI) utilizes a 50mm throttle body design with 12-hole injection nozzle fed by lightweight 50-psi pump to ensure optimum fuel atomization and precisely targeted fuel charge. System also achieves an improvement in fuel consumption.

PGM-FI system monitors throttle position, intake air and coolant temperatures, air pressure and gear position to accurately map fuel charge and ignition spark, significantly improving partial-throttle response and helping assure excellent rideability.

AC generator enlarged to service PGM-FI system. Two crankshaft position sensors quickly determine crank position to provide quick starts, hot or cold.

Twin-sump lubrication system separates the oil supply for the crankshaft, piston and valve train from the clutch and transmission. This ensures a cool supply of oil to the clutch, eliminates clutch and transmission material contamination of the engine oil and reduces the amount of circulating oil, allowing the oil pump size to be reduced.

Redesigned exhaust system incorporates a left-side cylinder head exhaust port, increasing header length and allows muffler to be positioned closer to center of mass, contributing to significantly improved weight distribution and handling.

Gear-driven balancer reduces vibration and drives the water pump.
New mechanical water pump seal improves durability.

Coolant flow rerouted outside engine cases via bolt-on flange/jacket, allowing reduction of crankcase and cylinder width, and overall weight.

Oil pump strainer now built into the engine case to reduce parts and weight.

Eight clutch plates handle the engine’s massive torque while the number of clutch springs is reduced from six to four. This reduces centrifugal weight, allowing the engine to rev quicker.

Kashima coating applied to the clutch basket, clutch center and pressure plate improve clutch life and clutch feel.

Numerous transmission modifications narrow transmission width and reduce weight without sacrificing durability.