1974–1976 Harley-Davidson SS/SX 175-250 Service Manual (P/N 99490-76)

Harley-Davidson’s SS/SX-175/250 Service Manual covers the SS-175, SX-175, SS-250, and SX-250, with pages revised 12-75. The factory model table lists the 1974 SX-175; 1975 SX-175, SX-250, and SS-250; and 1976-and-later SS/SX-175 and SS/SX-250 models.

Printable PDF and Wiring Detail

Search, navigation, and diagram detail: PDF text search and embedded bookmarks are not available. Small wiring labels require zooming; some key-switch contact numbers on the late-1975 Type C wiring sheet remain blurred.

The ZIP download contains one printable English PDF with 126 pages, including five opening cover, title, foreword, and contents pages.

Engine Rebuilding, Chassis Service, and Electrical Diagnosis

The following selected topics show the manual’s repair coverage rather than its complete contents. Other sections include headlamp aiming and speedometer and tachometer cable service.

• Engine rebuilding: Step-by-step procedures for engine removal, cylinder and piston inspection, crankcase separation, crankshaft rebuilding and truing, and final end-play adjustment.

• Wheels and brakes: Rear-chain service, front and rear wheel-hub work, steel and aluminum brake-sprocket assemblies, wheel spoking and truing, and brake disassembly.

• Forks and suspension: Separate Marzocchi, Ceriani, and Betor fork procedures, steering-head service, rear shock replacement, and rear-fork pivot adjustment.

• Clutch and transmission: Earlier and later clutch assemblies, clutch diagnosis and adjustment, kick-starter and shifter service, and separate transmission disassembly and assembly procedures.

• Electrical diagnosis: Build-specific wiring diagrams and troubleshooting for the alternator, ignition module, rectifier, ignition coil, battery, and ignition-light switch.

• Carburetor and lubrication: Starting, low-speed, and high-speed circuits; carburetor disassembly, float-level checking, fuel-supply service, and oil-pump adjustment, replacement, and bleeding.

• Exhaust and service references: SS and SX muffler service, alternate air-cleaner arrangements, lubrication charts, torque tables, capacities, gear ratios, clearances, and wear limits.

The foreword addresses readers performing basic maintenance and repair, while directing the factory-approved major repair methods to professional Harley-Davidson mechanics.

Engine Inspection and Rebuilding

The engine section covers the single-cylinder, loop-scavenged two-cycle platform beyond routine tune-up work. It distinguishes cylinder-head, cylinder, and piston work that can be performed with the crankcase in the frame from repairs requiring complete engine removal.

Cylinder-piston color-code tables identify preferred and acceptable combinations for the two engine sizes. Crankshaft coverage includes connecting-rod and crankpin replacement, flywheel alignment, runout checks, and thrust-washer selection after reinstallation.

The crankcase chapter describes separation both with the factory splitting tool and with ordinary tools under additional handling precautions. Its exploded crankcase view identifies the bearings, seals, and associated parts involved.

Chassis Configurations and Suspension Limits

Separate steel and aluminum rear-hub procedures distinguish their bearings, couplings, and brake-sprocket assemblies. The wheel section also separates quick-detach wheel removal from removal of the complete wheel and brake-sprocket assembly.

Fork service includes inspection, seal replacement, and assembly details for each manufacturer, supported by illustrations such as the Marzocchi fork exploded view. Fork-oil tables distinguish drained, wet forks from fully disassembled or flushed, dry forks.

The rear suspension section covers shock adjustment and replacement, plus rear-fork pivot and bushing work. The shock absorber assemblies themselves are not intended to be disassembled for internal repair.

Clutch, Kick Starter, and Gearbox Assembly

The later clutch has a separate plate-removal method using a special tool while the clutch remains installed. Clutch inspection also identifies the shell and primary gear as a matched replacement pair.

The later SX-250 gearbox requires different handling of loose bearing rollers and retaining washers. Assembly checks cover gear engagement, shaft rotation, and shifting before and after crankcase closure. Illustrations include the later SX-250 transmission exploded view, clutch exploded views, and starter cross-section.

Factory tool references include the 95500-29A wheel truing stand, 97358-74P crankcase splitting tool, 96650-30 crankshaft truing stand, 97362-74P carburetor float gage, 97361-74P transmission assembling tool, and 97360-74P ignition timing setting tool.

The right crankcase cover must come off evenly: damage to its mating surfaces can cause oil leaks after reassembly. Reversing a speedometer or tachometer cable so its thrust-collar end enters the drive mechanism can damage that mechanism.

Fuel Delivery and Oil-Pump Matching

Carburetor cutaway and operating-circuit drawings explain how starting, low-speed, and high-speed fuel delivery differ. Cleaning and inspection procedures cover jets, float valves, screens, and seals; the fuel-valve section distinguishes early twin-handle and later single-handle designs.

Oil pumps are build-specific. Different calibrations and displacement markings on their control levers help prevent selection of the wrong pump during repair. The manual covers adjustment, removal, replacement, and bleeding; a faulty pump is replaced rather than disassembled internally.

Gasoline liquid and vapor must be kept away from smoking, open flame, and sparks. The tank-repair section reserves welding repairs for qualified personnel and warns of explosion risk if fuel traces remain.

Wiring Variants and Fault Isolation

The wiring sheets distinguish Type A controls with the 71505-73P key switch; Type B controls with either the 71505-73PA or 71505-75P switch; Type C controls with the 71505-75P or 71514-75P switch; and the 1976-and-later layout. That breakdown matters when tracing faults or matching replacement switchgear to the build.

Electrical troubleshooting separates the ignition and battery-charging circuits. No-spark diagnosis includes charging-coil, pickup-coil, ignition-coil, and wiring checks; a doubtful ignition module is evaluated by substitution. Alternator-component exploded views supplement the wiring diagrams.

Separate service bulletins cover interim engineering changes and supplementary model information. This publication is a service manual, not an illustrated parts catalog.

Selected Float-Level and Crankshaft Specifications

The carburetor float-level section specifies 17.5–18.5 mm for the SX-175 and 23.5–24.5 mm for the SX-250, measured from the tops of both floats to the casting edge with the float valve seated.

After crankshaft reinstallation, the specified assembly end play is 0.002–0.004 in. (0.05–0.10 mm). The crankshaft section explains the associated measurement and thrust-washer selection.