1981 CB900C OEM Specifications

CB900C specs courtesy of Fernando Malvestuto (fmalve@mcg.org.ar)

Engine Four-stroke transverse four, air-cooled with dual chain-driven overhead camshafts and four valves per cylinder.
Bore x Stroke 64.5 x 69.0mm (2.54 x 2.72 in.)
Displacement 902cc (55.0 cu. in.)
Compression Ratio 8.8:1
Carburetion (4) Keihin 32mm constant-vacuum
Exhaust System Four into four
Air Filter Dry cartridge, disposable
Oil Filter Paper element, disposable
Ignition Battery-powered inductive, magnetically triggered
Oil Capacity (engine) 4.5 liters (4.7 qts)
Oil Capacity (transfer case) 0.6 liters (0.6 qts)
Oil Capacity (final drive) 0.2 liters (0.2 qts)
Fuel Capacity 13.6/3.0 liters (3.6/0.8 gal)
Electrical Power Three-phase A.C. generator, 266 watts, solid-state regulator
Battery 12V 14Ah
Headlight (high/low) 60/55 watts
Tail/stop lights 8/23 watts
Transmission Dual-range five-speed, constant-mesh, wet clutch
Primary Drive Hy-Vo chain and straight-cut gear, 2.04:1
Secondary Drive low..............Straight-cut gear, 0.72:1

high..............Straight-cut gear, 0.62:1

Tertiary Drive Shaft and spiral-bevel gear, 1.20:1
Final Drive Shaft and spiral-bevel gear, 3.091:1
Gear Ratios, overall low range...........(1) 12.96 (2) 9.77 (3) 7.59 (4) 6.33 (5) 5.26:1

high range..........(1) 11.09 (2) 8.36 (3) 6.50 (4) 5.42 (5) 4.50:1

Suspension
Front Coil/air-spring leading-axle fork
travel: 154mm (6.1 in.)
Rear Swing arm with (2) coil/air-spring shocks
travel: 95mm (3.8 in.)
Tires
Front Tubeless 110/90-19 62H Dunlop Qualifier F11
Rear Tubeless 130/90-16 67H Dunlop Qualifier 67H
Brakes
Front Hydraulic, dual disc, 276mm (10.9 in.) rotor with single-piston calipers
Rear Hydraulic, single disc, 296mm (11.7 in.) rotor with single-piston caliper
Wheelbase 1585mm (62.4 in.)
Rake/Trail 28.5º /114mm (4.5in.)
Seat Height 782mm (30.8 in.)
Ground clearance 160mm (6.3 in.)
Weight with tank full 276.4 kg (610 lbs)
Load Capacity 208.6 kg (460 lbs.)
 
Performance
Standing 1/4 mile 12.76 sec. @ 104.89 mph
Fuel consumption 27.2 mpg (15.8 km/l)
Range (main/reserve) 133.9/29.8 mi. (214.9/47.4 km)
Calculated speed in gears 
9500 RPM (low/high)

low range ..................(1) 52.8 (2) 70.1 (3) 90.2 (4) 108.2 (5) 130.2 mph

high range .................(1) 61.8 (2) 81.9 (3) 105.4 (4) 126.4 (5) 152.2 mph