About the Honda CB400A
Repair parts for the 400 twin with Honda’s Hondamatic transmission.
The CB400A brought Honda’s Hondamatic transmission to the 400 twin. A torque converter works with a two-speed semi-automatic gearbox and foot-operated range selection. The motorcycle also has a parking-brake system. Those features give the A its own transmission and control requirements alongside the manual Hawk twins.
Build a repair order around the Hondamatic
The service parts below cover four distinct jobs on a 1978 CB400A: engine sealing, front master-cylinder repair, rear brake renewal and fuel-tap replacement. Some also fit specific manual-Hawk years. For converter or transmission work, identify the individual gasket or seal needed and compare it with the package contents.
Know your motorcycle before choosing partsHonda CB400A Hondamatic and manual-Hawk differences
Shared twin-engine ancestry does not remove the Hondamatic’s distinct transmission and control requirements.
1978 Hondamatic
CB400A transmission and controls
The A uses a torque converter, two-speed semi-automatic transmission and parking-brake system.
Parts checkpoint: Choose an explicit CB400A application for transmission parts.
Manual Hawk twins
CB400T, Hawk I and Hawk II
Individual gaskets or chassis parts can list both A and T applications. Conventional Hawk clutch plates still need separate verification for a Hondamatic.
Parts checkpoint: Treat shared coverage as specific to the part listed.
Honda CB400T Hawk partsFour-cylinder alternative
CB400F Four
The original Four has a separate engine and carburetor application from the CB400A twin.
Parts checkpoint: Use the Four’s collection if that is the engine family you have.
Honda CB400F Four parts
Frame, engine & fitted componentsHonda CB400A identification checklist
Use these details to match your motorcycle and any replacement assemblies before ordering.
- Record the complete frame/VIN, model year and engine number.
- Identify the Hondamatic engine and its range-selection and parking-brake controls; photograph them if parts are missing.
- Read the carburetor identification before ordering fuel-system repair parts.
- Identify the front master cylinder, front caliper and rear drum separately; record the tank mounting and outlet arrangement for a fuel tap.
Contact PartsNMore with clear photos of the frame/VIN, engine number and the part’s markings, plus any known component changes.