1970–1978 Harley-Davidson Sportster XL / XLH / XLCH / XLT-1000 Service Manual (P/N 99484-78)

This Harley-Davidson factory service manual, P/N 99484-78, covers maintenance and repair for the 1970–1978 Sportster XL, XLH, XLCH, and XLT-1000. Its sections cover Product, Chassis, Engine, Transmission, Electrical, and Miscellaneous service information.

• Engine repair: Cylinder-head and valve service, cylinder and piston inspection, crankcase disassembly, flywheel truing, cam timing, and oil-pump overhaul.

• Fuel systems: Tillotson, Bendix, and Keihin carburetor inspection, rebuilding, adjustment, and troubleshooting, plus air-cleaner and fuel-supply service.

• Clutch and transmission: Dry- and wet-clutch service, kick-starter and electric-start drive repair, internal gearbox inspection, and transmission assembly.

• Chassis and brakes: Wheel spoking, rim truing, telescopic fork rebuilding, drum- and front disc-brake service, hydraulic bleeding, and fiberglass body repair.

• Electrical diagnosis: Model-specific wiring diagrams, generator and regulator testing, ignition timing, battery checks, and Prestolite and Hitachi starter-motor overhaul.

• Workshop references: Lubrication schedules, fastener torque tables, fluid capacities, wear limits, special-tool references, and exploded component views.

The foreword addresses professional Harley-Davidson mechanics for major repairs; the overhaul procedures call for precision measuring equipment and dedicated shop tools.

Cylinder Heads, Crankcases, and Lubrication

The engine section details cleaning, inspection, removal, and installation for cylinder heads, pistons, and related assemblies. Valve work extends to guide replacement, seat reconditioning, rocker-arm bushing replacement, and tappet adjustment.

Bottom-end repair includes connecting-rod bearing fitting, flywheel alignment, pinion-shaft bearing work, and crankcase assembly. The manual distinguishes the earlier gear-type oil pump and timed breather from the later gerotor pump, with separate inspection and assembly information for each design.

The piston installation notes warn that an insecure piston-pin lock ring can escape its groove and damage both the piston and cylinder.

Carburetor Testing and Adjustment

The Tillotson section covers diaphragm operation, inlet-needle leakage testing, and main-nozzle and economizer check-valve checks. Bendix coverage explains its fuel, idle, and accelerating systems; the Keihin section adds float-setting illustrations and a dedicated Keihin Carburetor Trouble Chart.

That chart links symptoms such as hard starting, poor idling, and poor acceleration to checks on the float, jets, air passages, and accelerating pump, helping narrow a fuel-system complaint before carburetor disassembly. Tool references include the Carburetor Leakage Tester, Part No. 94750-68, and Float Level Gauge, Part No. 94752-77.

Clutch Diagnosis and Gearbox Repair

Separate procedures address the 1970 dry clutch and 1971-and-later wet clutch, including their release mechanisms and spring adjustments. The Clutch Diagnosis Chart separates slipping from dragging or incomplete release and directs attention to the relevant controls and internal components.

Gearbox coverage goes beyond removal: it describes shifter-mechanism inspection, mainshaft and countershaft assembly, gear engagement checks, and end-play measurement with selective washers. The wet-clutch section identifies Clutch Spring Compressor, Part No. 97178-71.

Wheels, Forks, Brakes, and Bodywork

The Wheel Service Chart addresses handling-related checks, while the Sportster Tire Chart identifies wheel and tire combinations. Wheel lacing, rim centering, bearing inspection, and wheel alignment receive their own procedures and illustrations.

Fork coverage includes the Front Fork and Shock Absorber exploded view, with distinct construction and service details for the different fork designs. Rear suspension work covers spring and mounting components; the hydraulic shock absorber unit itself is replaced if faulty.

Brake sections distinguish front drum brakes from the different front disc-caliper designs and cover master-cylinder inspection and hydraulic bleeding. Fiberglass repair extends from gel-coat damage to patching holes, punctures, and breaks.

Keep the workspace well ventilated and secure the motorcycle on a suitable stand before mechanical disassembly.

Charging, Ignition, and Starter Diagnosis

The electrical section combines wiring diagrams and color-code keys with generator output, field-coil, and armature tests. Regulator procedures distinguish Delco-Remy and Bosch units from the later electronic regulator, while starter coverage separates Prestolite and Hitachi construction.

The regulator section warns that reversed generator polarity can burn relay contacts. Ignition coverage includes breaker-point inspection, advance-mechanism service, strobe timing checks, coil troubleshooting, and spark-plug inspection; the Bulb Chart identifies lighting and indicator applications.

Selected Valve Fits, Head-Bolt Torque, and Oil Capacity

The engine specifications list intake-valve stem-to-guide fit at .0015–.0035 in. The cylinder-head installation procedure gives a final head-bolt torque of 65 ft-lbs.

The lubrication section specifies an oil-tank capacity of 3 quarts at the FULL mark, including the XLCH tank.

PDF Search, Diagram Detail, and Included Pages

Finding text and reading wiring: Manual text is not searchable, and there are no embedded PDF bookmarks. Dense wiring-diagram areas call for zooming to read the small component numbers and wire-color codes.

Supplied as one printable, English-language PDF with 235 pages, including the front and back covers, foreword, and contents pages.