1981 Honda CB900C Parts

Parts and fitment guide for your 1981 CB900C

This 1981 Honda CB900C Custom collection includes stock-airbox and paper oil-filter service parts. The linked 73-0139 airbox boot set lists the 1980–82 Custom, but shared intake fitment does not establish interchangeability for the motorcycle’s other assemblies.

Browse by repair

• Engine parts — engine components, seals and service items.
• Fuel-system parts — fuel delivery, intake and air-filter listings.
• Electrical parts — ignition, controls and electrical accessories.
• Brake & clutch parts — brake and clutch service listings.
• Suspension & wheels — fork, wheel and suspension items.
• Exhaust parts — exhaust components and hardware.

Selected parts for the 1981 CB900C

Check each listing for model fitment, dimensions and included quantities before ordering.

• Stock air filter — for the stock airbox; check modified intakes separately.
• Airbox boot set — four carb-to-airbox boots; check the clamp requirements in the listing.
• Oil filter — paper filter element; O-rings, springs and washers are separate.

Identify your CB900C (1981)

Compare the motorcycle’s identifiers with its original-market documentation.

• Identifiers to record — complete frame/VIN and engine markings

Use the linked model chart as a reference alongside those records, especially when registration year and model year differ.

View the model reference chart

For help locating identifiers, see our Honda CB model identification guide.

Keep the two sides of the intake distinct

The selected 73-0139 boots connect the carburetors to the airbox. The set contains one each of four different replacement references, 17251-438-000 through 17254-438-000. Engine-side holders are different parts. For this airbox set, the listing specifies 60–65mm band clamps 15-0673 when replacement clamps are required.

Fitment questions

Does replacing the air filter also complete the crankcase-breather service? No. Honda lists breather cleaning separately. For the original U.S.-specification system, the maintenance notes call for more frequent service after riding in rain or at full throttle. Include that check when servicing the stock airbox.

Is reassembling the carburetor rack the final step after an overhaul? Honda’s common service guidance calls for synchronization after multiple carburetors are reassembled. Have that check completed using the model-specific procedure; new airbox boots do not replace it.

Related CB900C collections

• 1980 CB900C parts
• 1982 CB900C parts

Need help checking a part? Contact VintageCB750 with the model year, original market, frame and engine markings, and photos of the component.