Technical Articles

CARB O-RING SIZES: CB350, CB400, CB500, CB550

When rebuilding carbs on the old Honda fours with press-in main jets, you will often find that all the metal parts are fine after a good cleaning, and all that you really need to buy are new O-rings. Honda doesn’t sell the individual O-rings separately….

instead you have to buy a complete carb kit at $10 to $15 per carb. I found an industrial O-ring supplier who was willing to do small-volume counter sales, and was able to get new O-rings at about 50 cents per carb. Sizes are:

Main Jet: 1.2mm cross-section x 3.5 mm ID

Float Seat: 1.5 mm cross-section x 5 mm ID

Float Bowl Drain Screw: AS568-009 (7/32″ ID x 11/32″ OD)

———————————————————— CB550:

Shifter lever seal = inside diameter – 14mm, outside diameter – 24mm, depth – 5mm

And the one behind the sprocket = I.D – 33mm, O.D. – 57mm, depth – 7mm

Honda Wiring Colors

Color Use Origin Destination
Black Switched Hot Ignition Switch Fuses
Black Switched Hot Ignition Switch Handlebar Switch
Black Switched Hot Ignition Switch Starter Switch
Black Switched Hot Ignition Switch Voltage Regulator
Black/Brown Fused Hot Fuse Box Oil Light
Black/Brown Fused Hot Fuse Box Neutral Light
Black/Red Fused Hot Fuse Box Starter Switch
Black/White Ignition System Hot Kill Switch Coils
Blue/White Switched Hot Starter Switch Dimmer Switch
Brown Tail/Rear Light Brown/White Ignition Switch Brown Lead
Brown/Black Fused Hot Fuse Box Brown/White Lead
Brown/White Running Lights Brown/White Turn Signal Switch
Brown/White Gauge Lights Brown/White Gauges
Brown/White Taillight Brown/White Ignition Switch
Green Ground Load Ground
Green/Red Starter Safety Circuit Starter Relay Clutch Switch
Green/Yellow Brake Light Brake Light Switch Brake Lamp
Gray Hot Turn Signal Flasher Turn Signal Switch
Light Green Horn Circuit Horn Switch Horn
Light Green/Red Neutral Circuit Neutral Switch Neutral Light
Orange Left Turn Signals Turn Signal Switch Left Turn Signal Lamp
Light Blue Right Turn Signals Turn Signal Switch Right Turn Signal Lamp
Orange/White Left Running Lights Turn Signal Switch Brown Lead
Light Blue/White Right Running Lights Turn Signal Switch Brown Lead
Red Hot Battery Ignition Switch
Red/White Charging Lead Rectifier Battery
White Lo Light Dimmer Switch Headlight
Blue Hi Light Dimmer Switch Headlight
White/Green Fused Hot: Turn Signal Fuse Box Flasher
White/Green Fused Hot: Horn Fuse Box Horn
White/Green Fused Hot: Brake Light Fuse Box Brake Light Switch
Yellow Charging System Stator Rectifier
Yellow & Blue Ignition Points Coils
Yellow/Red Starter Circuit Starter Switch Starter Relay