Powerful new Honda sports roadster — the CB900F four

Press, 26 April 1979, Page 25

Powerful new Honda sports roadster — the CB900F four

The first shipments ot Honda’s new super sports production roadster, the CB9OOF, to reach New Zealand met with a demand which took many dealers by surprise. The impressive specifications and the very fashionable appearance of the bike put it, almost overnight, among the best sellers. Claimed to be the lightest and fastest machine in its class, the CB9OOF has been developed from the threetime winner of the European endurance championship, the RCB. The basic design of the engine used in both the CB9OOF and the RCB is the same. Like the RCB, the CB 900 F features a fourcylinder, double overhead camshaft engine with four valves to each cylinder to provide efficient breathing at high engine speeds. It also has an oil cooler. Although the CB9OOF has a displacement of only slightly more than 900 cu cm. its formidable power plant delivers 95 b.h.p. at 9000 r.p.m. (DIN measured at the crankshaft.) and boasts a maximum torque of 7.9 kg-m at -8000 r.p.m. This performance has been achieved through a number of special features, such as four in-line carburettors of the improved constant vacuum type, each with a 32mm main venturi. An acceleration pump enables lightning-fast starts. Optimum breathing efficiency is assured by two

26mm intake valves ant two 22.3 mm exhaust valve: in each cylinder. Thi Honda four-into-two ex haust system is said ti improve the efficiency o exhaust emission and ti allow a greater output o power. Like the CBX, the Cl

900 F has a fully transistorised ignition coupied with a mechanical advance system. This maintains timing within a range of BTDC 10 deg. to 38.5 deg. according to engine r.p.m. The engine of the CB 900 F sounds quiet and smooth. This has been made possible by several significant improvements to the drive train and transmission. An unusual feature of the CB9OOF is its fully adjustable FVQ dampers on the rear shocks. These have three adjustable settings for rebound and two for compression, allowing the rider a choice of six different combinations. In addition, of course, the spring preload is adjustable with five settings. The FVQ damper is the first fully adjustable damper to be fitted on a standard production model. The CB9OOF is a sports bike, but can double as a touring bike. Thanks to its powerful engine, the bike can cover a standing 400 m in a mere 11.75 s and can corner with a dynamic bank angle of 43 deg. This factor contributes to the remarkable handling per-

formance of this machine on both road and track. The CB9OOF is delivered complete with all the fine features demanded of a touring bike, such as a comfortable double seat, Comstar wheels, a long-life chain, and a large-capacity, 20 litre fuel tank which enables non-stop stages of more than 300 km. Special attention has been devoted to the braking system in order to match safety with performance. The CB9OOF employs a three-disc hydraulic brake system with single front and double rear discs whose ratio and balance provide excellent braking control. It is available in two colours, red and silver. SPECIFICATIONS Engine: Air cooled 4-slroke DOHC; oil cooler with 2220 K cs/h rating four-cylinder in-line, four valves per cylinder. Capacity: 901 c.c. Bore and stroke: 64.5 mm x 69.0 mm. Compression ratio: 8.8:1. Carburation: Four constant vacuum type VB carburettors, with accelerator pump. Maximum claimed power: 69.9 Kw 95 PS at 9000 r.p.m. (DIN). Maximum . claimed torque: 7.9 kg-tn at 8000 r.p.m.

Transmission: Wet multiplate type clutch, disc with coil spring; 5-speed gearbox with dog clutches and hook shifting. Drive chain, long-life roller chain.

Internal ratios: 2.533; 1.789, 1.391; 1.160 and 1.000 to 1.

Electrical equipment: Fully transistorised ignition system with mechanical advance. Electric starter; battery capacity 12V-14Ah. 180 mm headlight; direction indicators; stoplight. Fuel capacity: 20 litres, including 4.5 litre reserve; recessed lockable cap. Frame: Double-cradle steel tube frame.

Suspension: Telescopic front fork with double-acting hydraulic shock absorbers. Swing arm pivoted rear with progressive spring; five position adjustable. Adjustable FVQ damper with 3-stage (rebound) and 2-stage (compression). Wheels: All-aluminium Comstar wheel with cast hub.

Tyres: Universal tread, tube less. 3.25V19-4PR front; 4.00V184PR rear.

Brakes: 276 mm diam. double disc with floating caliper, front; 296 mm diam. single disc with floating caliper, rear. Dimensions: Length 2240 mm; width 795 mm; height 1.125 mm. Wheelbase 1515 mm; seat height 815 mm; ground clearance 150 mm.

Weight: 232 kg dry; 253 kg wet. Weight to power ratio (kg/PS) 2.4.

Claimed performance: Acceleration 0-80km/h, 2.65; 0-120km/h, 4.9 sec; 0-150km/h, 8.8 s; 0-400 m, 11.755; O-1000m, 22.85.