Honda CB100, CL100, SL100, CB125S, CD125S, SL125 1971–1985 Service Manual (P/N 6210703)

• Covers 1971–1985 Honda CB100, CL100, SL100, CB125S, CD125S, SL125, and TL125 variants (100cc and 125cc single-cylinder powerplants).
• Original OEM factory data based on the 1971 first edition litho in Japan (P/N 6210703), acting as the primary reference for the launch build.
• Packed with 21 detailed exploded-view diagrams, 10 electrical wiring schematics, and 14 technical specification tables.
• Details the A.C. generator, selenium rectifier, contact breaker points, primary kick starter, and centrifugal oil filter.
• Outlines gear shift mechanism, cam chain tensioner, ignition coil, spark advancer, and steering stem procedures.

Shop Utility and Technical Scope

Time is money in the shop. This 101-page PDF manual expedites your workflow by breaking down the engine, chassis, and electrical systems into five dedicated mechanical sections, supplemented by a comprehensive TL125 appendix. It provides the exact factory reference points needed to run a proper diagnostic and execute a reliable fix for routine maintenance and complex teardowns alike.

To help you keep labor-intensive, high-ticket jobs in-house, the guide supplies step-by-step instructions for tasks that typically require a specialty workshop, such as complete telescopic front fork overhauls including oil seal replacement, wheel rim truing via spoke retightening, and precise cylinder compression checks. The manual walks you through critical baseline adjustments, including valve tappet clearances, carburetor idle and mixture, ignition timing, and clutch free-play. It also outlines strict inspection procedures for engine oil, drive chain tension, and the 6V electrical charging circuits. When you need to split the cases for a major repair, the drivetrain chapters map out the exact assembly sequence for the clutch, transmission, and crankshaft, while the chassis sections cover the front and rear suspension, brake systems, and steering unit components. To further accelerate troubleshooting, the content features specific visual aids like a lubrication system flow chart, carburetor setting table, A.C. generating specifications chart, maintenance schedule table, and TL125 wiring diagram.

Factory Specifications and Tolerances

Accurate component measurement is crucial when setting up vintage powerplants. This documentation delivers the mandatory wear limit tolerances for pistons, cylinder bores, and valve seats. Engine rebuilders will find critical baselines, such as the standard cylinder compression pressure at 12 kg/cm² (170 psi) and the specific intake valve clearance of 0.05 mm. You also get detailed electrical testing benchmarks, including the required 10 MΩ magneto pick-up coil insulation resistance.

When servicing these overhead-cam singles, mechanics frequently encounter severe top-end wear. Because the camshaft rotates directly in the aluminum cylinder head, any oil starvation from a neglected centrifugal oil filter will instantly score the casting. Additionally, the original 6V charging system relies on a healthy battery to absorb excess current; operating the motorcycle with a dead or disconnected battery can quickly fry the selenium rectifier and stator coils.

Working on vintage motorcycle components carries inherent risks, especially around pressurized fluids, moving engine parts, and electrical circuits. Always follow standard workshop safety protocols and verify your setup against these original factory values.