CB550K Serial Numbers

Model Model Year Starting Frame # Starting Engine #
CB550 K0 1974 CB550-1000001- CB550E-1000001-
CB550 K1 1975 CB550-1200005- CB550E-1029182-
CB550 K2 1976 CB550-1230001- CB550E-1067334-
CB550 K3 1977 CB550-2000007- CB550E-2000001-
CB550 K4 1978 CB550-2100001- CB550E-2100001-

CB550F Serial Numbers

CB550 F1 1975 CB550F-1000002- CB550E-110004-
CB550 F2 1976 CB550F-2000003- CB550E-1109887-
CB550 F3 1977 CB550F-210001- CB550E-1135380-

CB550K Models

1974   CB550 K0

1974 CB550 K0

The CB550K was introduced in 1974 as an upgrade to the CB500K which it closely resembled.  The bike came in three colors, Flake Sunrise Orange, Boss Maroon Metallic, and Freedom Green Metallic with a two-tone tank paint scheme featuring the base color with a black panel and a gold accent stripe.  The side covers were painted the base color.

1975 CB550 K1

1975 CB550 K1

The CB550 K1 had dark green instrument faces and featured a gold and black tank stripe.  Color options included Candy Jade Green and Flake Sunrise Orange.

1976 CB550K2

The 1976 model was offered in Candy Garnet Brown.  The tank paint scheme was carried over from the 1975 model year.  Aside from the body color, the only significant change was to light green instrument faces.

1977 CB550K3

The CB550 K3 came in Candy Garnet Brown and Excel Black.  The tank was painted one color and featured a wider stripe in red and gold.  The emblem "550 Four K" was added to the side cover.  The gas filler was recessed under a locked cover.

1978 CB550K4

The 1978 model was available in Candy Alpha Red and Excel Black.  The tank style was retained from 1977 with a gold pinstripe added to the side cover.  The seat was changed to a dual contour seat with a stepped section for the passenger.

CB550 F Models

1975 CB550F0

The CB550F was styled after the CB750F and featured a 4 into 1 exhaust.   The paint scheme was a simplified one-color scheme without pin striping.  For this model year, the available colors were Candy Sapphire Blue and Flake Sunrise Orange.  The side covers featured a '550 Four' decal.  The instrument faces were dark green with white numbers.

1976 CB550 F1

For 1976, the colors were blue and orange, but now called Flake Sapphire Blue and Shiny Orange.  The seat covering was a dark brown and the instrument faces were light green with white numbers.

1977 CB550 F2

The 1977 model came in Candy Sword Blue or Candy Presto Red.  A wide gold tank stripe was added and the side covers were painted black.  The seat was changed back to black and the fork boots were eliminated.

CB550 F/K Specifications

The CB550K and CB550F models were essentially identical with some minor difference in the frame and trim specs. The following table of specifications applies to both models - all years.
Engine Air cooled 8-valve SOHC transverse four
Bore X Stroke 58.5 x 50.6mm
Capacity 544cc
Comp. Ratio 9.0:1
Claimed power 50bhp @ 8,500rpm
Torque 30.4ft-lb @ 7,500rpm
Carburetors 4 x 22mm Keihin
Gearbox 5-speed
Tires, front 3.25 x 19in
Rear 3.75 x 18in
Brakes, front Lining Area = 288.8 sq. cm X 2
Rear Lining Area = 169.6sq. cm X 2
Suspension, front Telescopic forks, 35mm
Caster Angle 64 degrees
Trail Length 105mm (4.1in)
Rear Twin shocks with adjustable pre-load
Wheelbase 1,405mm (55.3in)
Seat Height 805mm (31.7in)
Weight 192kg (423lb) wet, F model slightly less
Fuel capacity 14 liters (3.7 gallons)
Top speed (approx.) 102mph (164kph)