CB550

History

There was never much bad to say about the Honda 500 Four, so why enlarge its bores by a mere 2.5 millimeters to make a 550? Several reasons: first, and probably the least important, is the presence of Suzuki’s 550 - Honda didn’t want to lose any sales over a piffling 50ccs; second, the consumer woudld be more likely to absorb a price increase to $1,600 without squawking if their getting more motorcycle for the money; and, third, the extra displacement - tiny as it is (a guppy could barely turn around in a 50cc fishbowl) - actually added a noticeable amount of mid-range power and torque.

Cosmetically, the CB550 was a smaller version of the CB750 from the 4 pipe K model to the four-into-one F model. Technical Specifications for the CB550 remained virtually unchanged over the model lines. Like it’s larger sibling, the 550 proved a reliable, comfortable, easy-to-maintain, every-day motorcycle. Perfect for the time.

Model Guide

CB550K

Serial Numbers

Model Model Year Frame 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-

1974 CB550K0

Boss Maroon Metallic Flake Sunrise Orange Freedom Green Metallic

The CB550K was introduced in 1974 as an update to the CB500 in the US market. The models were cosmetically similar; mechanically, aside from the extra 50cc displacement, significant improvements in the transmission. The 1974 CB550K was offered in three colors: Flake Sunrise Orange, Boss Maroon Metallic, and Freedom Green Metallic. The tank featured a two-tone paint scheme with the base color accented by a black panel and gold striping. The side covers were painted the base color.

1975 CB550K1

Candy Jade Green Flake Sunrise Orange

The CB550 K1 received dark green instrument faces and the tank featured a gold and black accent stripe. Two color options were available, Candy Jade Green and Flake Sunrise Orange.

1976 CB550K2

Candy Garnet Brown

The 1976 model was offered in a single color, Candy Garnet Brown. The tank paint scheme was carried over from the 1975 model. The only other significant change was to the instrument faces, which were now light green.

1977 CB550K3

Candy Garnet Brown Excel Black

The 1977 CB550 K3 paint options were Candy Garnet Brown and Excel Black. The tank was now painted in a single solid color and featured a wider accent stripe in red and gold. The gas filler was now recessed under a locking cover panel. The side covers featured a new emblem, “550 Four K”. In the US, the carburettors were changed to meet emmissions requirements. The 4-into-4 exhaust was restyled.

1978 CB550K4

Candy Alpha Red Excel Black

The 1978 model was offered in two colors, Candy Alpha Red and Excel Black. Changes from 1977 include a gold pinstripe on the side covers and a dual contour seat with a stepped section for the passenger.

CB550F

Serial Numbers

Model Model Year Frame Engine
CB550 F0 1975 CB550F-1000002- CB550E-110004-
CB550 F1 1976 CB550F-2000003- CB550E-1109887-
CB550 F2 1977 CB550F-210001- CB550E-1135380-
1976 Shiny Orange 1977 Candy Sword Blue 1977 Candy Presto Red

1975 CB550F0

The CB550F featured a 4 into 1 exhaust similar to the CB750F. The tank was painted in a solid color, Candy Sapphire Blue or Flake Sunrise Orange without pin striping. The side covers featured a ‘550 Four’ decal. Instrument faces were dark green with white numbers.

1976 CB550F1

The colors options for this model year were Flake Sapphire Blue and Shiny Orange. The seat covering was dark brown and instrument faces changed to light green with white numbers.

1977 CB550F2

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

Specifications

The CB550K and CB550F models were mechanically identical throughout the model years. There were some carburettor changes in the 1977/1978 years which are detailed in the tech library.

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
Brakes, rear Lining Area: 169.6sq. cm X 2
Suspension, front Telescopic forks, 35mm
Caster Angle 64 degrees
Trail Length 105mm (4.1in)
Suspension, 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)