1969–1982 Honda CT70, CT70H, CT70K1, CT70HK1 Parts Catalog (P/N HC 37507)

• Identifies CT70, CT70H, CT70K1, and CT70HK1 components with individual application columns and model-specific exploded plates.
• Breaks down the cylinder and cylinder head, camshaft and valve train, generator, cam-chain tensioner, crankcase and oil pump, Keihin Seiki carburetor, kick starter, and gasket groups.
• Separates right-crankcase-cover, clutch, gearshift-fork/drum/spindle, and transmission listings for CT70/CT70K1 and CT70H/CT70HK1 configurations.
• Maps the steering handle, headlight and speedometer, front fork and cushion, wheels and brakes, seat and air cleaner, fuel tank, muffler, rear suspension, drive-chain case, and frame-body assemblies.
• Covers electrical and service-kit items through illustrated wire-harness/battery, ignition-coil, rectifier, combination-switch, tool-set, and gasket-set listings.
• Records Honda codes, part numbers, model application, supersessions, unavailable items, and engine/frame serial breaks for build-specific repair part selection.

This 99-page PDF contains American Honda Parts Catalog H/C 37507, 2nd edition, dated December 1973. It is suited to restorers, parts-counter staff, and experienced owners who need factory part identification and already have the appropriate shop manual for repair procedures. Numbered callouts on the exploded illustrations correspond directly to the adjacent descriptions and application data, making the catalog useful for checking an assembly before ordering.

Model and Serial-Number Coverage

The identification pages cover CT70 and CT70H frame numbers 100001 through 1999999, followed by the CT70K1 and CT70HK1 configurations using CT70 and CT70H frame prefixes from 2000001 onward. Within the parts tables, the remarks column narrows certain changes to much smaller production breaks.

The cylinder listing changes at CT70-226905 and CT70H-143001, while the CT70 gearshift fork uses the same 226905 break. Handle levers change at CT70-186005. The Carburetor Set table divides the CT70H carburetor assembly at 150721 and the CT70 packing, top, and throttle-valve sets at 270641. These distinctions help keep repair parts matched to the correct production build.

Engine and Drivetrain Identification

The Left Crankcase Cover/Generator section distinguishes Hitachi and Mitsubishi contact breakers, condensers, AC generator assemblies, flywheels, stators, and lighting coils. Separate clutch and transmission plates make the 70/K1 and H/HK1 configurations visible; the H/HK1 transmission table includes third-gear components in addition to the low, second, and top-gear parts. The crankshaft and piston section lists standard and oversize piston and ring options, while the carburetor pages separate complete assemblies from packing, float-valve, jet-needle, throttle-valve, top, and float-chamber sets.

Representative exploded plates include Cylinder/Cylinder Head, Left Crankcase Cover/Generator, Gear Shift Fork/Drum/Spindle, Carburetor (Keihin Seiki), Front Fork/Front Fender, and Wire Harness/Battery. The illustrations show how individual pieces relate within an assembly; they are not disassembly or reassembly instructions.

Frame, Running Gear, and Electrical Parts

The frame group carries separate 70/H and K1/HK1 plates where the builds differ, including the headlight/speedometer, front fork/fender, front cushion, and taillight/rear-fender groups. Wheel and brake listings identify hubs, rims, axles, brake panels, shoes, cams, arms, bearings, seals, sprockets, drive chains, and adjusters. Color- and finish-specific entries are retained for frame bodies, headlight cases, rear cushions, rear forks, and chain cases.

Electrical coverage is limited to parts identification. The wire-harness/battery plate and list identify the ignition coil, battery, selenium rectifier and superseding rectifier, fuse connectors, combination switch, battery box, mounting hardware, and harness components, but do not provide circuit tracing or a wiring schematic.

Ordering Notes and Catalog Scope

The opening instructions explain Honda's part-number structure, the H/C field, reference-number system, left/right conventions, abbreviations, and how engine or frame breaks are marked in the remarks column. Tables also flag superseded part numbers, replacement numbers, and items listed as not available. A separate tool-set page identifies the original onboard tools, including the spark-plug wrench and tappet-clearance adjusting gauge.

The thread-change notice distinguishes wrench-size changes from actual pitch changes. Modified-pitch fasteners are not interchangeable with the earlier type; forcing the wrong bolt, nut, or screw can strip the threaded parts. Because this is a parts catalog rather than a repair manual, it does not contain repair sequences, diagnostic tests, torque or clearance specifications, oil capacities, tire pressures, or wiring diagrams. Use the applicable Honda shop manual and qualified service practices for engine, brake, steering, or suspension work.