Honda CB900C CB900F CB900 1980-1982 Service Manual

Honda essentially hijacked the same engine to build two bikes with opposite personalities. Motorcycle Classics' own retrospective calls the CB900C's mission blunt: as the "Factory Custom" niche exploded in 1980, Honda stretched its proven 750cc four-valve inline four to 900cc and laid back the ergonomics — pulled-back bars, stepped seat, forward pegs — to compete against Suzuki's GS850/1100GL and Yamaha's XS1100 Special. The CB900F, sold in the US market for just 1981-1982 (after several years of European-only availability), took the exact opposite approach: a genuine sport bike Cycle magazine called "one of the best performance buys on the market," praised for "broad, generous power, and accurate, inspiring handling."

Both share the 901-902cc air-cooled DOHC inline-four architecture, 16 valves, pent-roof combustion chambers, fed by four carburetors — but the C runs a genuinely more complex driveline: a crossover shaft system incorporating two pairs of gears, giving it a 2-speed "Select Range" secondary transmission in its own transfer case with a dedicated trochoidal oil pump. Cycle magazine counted "20 gears, six shafts, a dozen bearings, three torque cushions, a U-joint and assorted couplings" in the full crank-to-rear-wheel connection — genuinely elaborate engineering that delivered 10 effective forward gears and reported 50 mpg fuel economy when kept in high range. The CB900F, by contrast, stuck with a straightforward chain-drive 5-speed gearbox, delivering a claimed 89-95 hp at 8,500-9,000 rpm and a genuine 139 mph top speed in period testing — none of the C's mechanical complexity, all of it aimed at outright performance.

Chassis hardware reflects the same divergent missions: the CB900C ran front and rear air-assisted suspension with the TRAC anti-dive system (shared with the later 1983 CB1100F) and shaft final drive, tipping the scales at a substantial 259kg (571 lbs) dry. The CB900F used a steel twin-downtube frame with air-assisted telescopic forks and adjustable twin rear shocks, weighing meaningfully less at 233-241kg depending on model year, riding on Bridgestone Mag Mopus tires. 1982 brought detail updates to the F specifically: graphics matching the CB750F, a new petcock with integrated fuel strainer, and updated Bridgestone tire fitment.

This factory service manual covers the procedures, torque specs, and diagrams needed to keep a 1980-1982 CB900C or CB900F running the way it was built to.