reprinted from Automotive Engineering, May 1998
Honda's 1998 motorcycle models
For the company's 50th anniversary, it has introduced an all-new 1.1-L Cruiser and updated its Open Class CBR900RR. Among the exclusive 1998 Shadow Aero features is a liquid-cooled 1.1-L V-twin, single-pin crankshaft engine, using rubber engine-mounting, a smooth-shifting five-speed gearbox with chromed heel-toe shifter, and a nearly 16-L gas tank. The Shadow Aero has a length of 2540mm with a low, 725-mm seat height; its casual riding position; its low, 975-mm-wide handlebar and saddle-style seat offers all-day comfort and custom appearance.
The 45° V-twin engine uses a three-valve cylinder head design and two spark plugs per cylinder for efficient combustion at all speeds, and hydraulic valve-lash adjusters make routine valve adjustments a thing of the past. The steel frame provides the 1679-mm wheelbase a low custom stance. Front forks measuring 41 mm provide 150 mm of travel for riders. Units use ultra-wide, low 140/80-17 front and 170/80-15 rear tires. There are many more features and a sizeable option list.
The updated CBR900RR uses new RC45-inspired aluminum composite cylinder sleeves, which are high-pressure formed from sintered aluminum powder impregnated with ceramic and graphite. They are 0.6kg lighter and provide better wear resistance and superior heat dissipation than the steel units they replace. Power output has increased to 92 kW, and 89 N·m of torque is now available. The dry mass has been brought down to 180 kg. A new six-speed gearbox has revised ratios and will provide a 3% higher top speed. Cooling efficiency has been boosted by 6%.
Among the first uses of a significant technology on a mass-production motorcycle are redesigned front brake calipers with larger pistons, having a special nickel-plate surface treatment to enhance brake-lever feel under repeated hard braking, and a high-tech instrument cluster that is 0.4 kg lighter and 40 mm thinner than before. Overall swept braking area is up by 14%. The ultra-compact 919 cm3, DOHC, liquid-cooled, inline four engine uses a one-piece upper crankcase/cylinder assembly, right-side cam-drive design, and a narrow 32° valve angle. The 16-valve head and a radical combustion chamber design provide an 11.1:1 compression ratio. The lightweight, tuned frame with triple-box construction and light, open-ribbed, die cast swingarm-pivot plates is said to offer excellent torsional and lateral rigidity for handling and feel.