Category:
Iconic American V-twin motorcycle
Competitors Era:
BSA Rocket 3, Triumph Bonneville, Norton Commando, Kawasaki Z1, Yamaha XS650
Engine Architecture:
Air-cooled, 45-degree V-twin
Design Philosophy:
Simplicity, ruggedness, and performance-oriented for its time
Historical Significance:
Represents a significant era of Harley-Davidson's evolution, popular for custom builds and classic restoration
Applicable Years:
1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978
Estimated Pages:
Estimated 300-500 pages (typical for comprehensive repair manuals of this era)
Type:
Repair Service Manual
Engine:
Complete engine overhaul, carburetor tuning, ignition system, lubrication, cooling (air-cooled), exhaust system
Transmission:
4-speed transmission service, clutch operation, gear shifting mechanisms, primary drive
Chassis:
Frame, suspension (forks, rear shocks), steering, wheels, spokes, tires
Brakes:
Drum brake systems (front and rear), brake linkages, adjustment procedures
Electrical:
Wiring diagrams, lighting system, charging system (generator/alternator), battery, ignition switch, starter motor, horn
Fuel System:
Fuel tank, fuel lines, fuel petcock, carburetor (e.g., Keihin, Linkert) disassembly and servicing
Bodywork:
Fenders, fuel tank mounting, seat assembly, minor body panel adjustments
Maintenance:
Scheduled maintenance, oil changes, filter replacements, chain adjustment, spark plug replacement, lubrication points
Troubleshooting:
Diagnostic charts for common problems, symptom-based troubleshooting guides
Repair:
Step-by-step repair instructions for all major components, disassembly and reassembly procedures
Adjustments:
Carburetor adjustments, ignition timing, clutch and brake lever adjustments, suspension settings
Depth:
Comprehensive, suitable for professional mechanics and experienced DIY enthusiasts. Covers detailed internal engine components, transmission rebuilds, and electrical system diagnostics.
Configuration:
Air-cooled, 45-degree V-twin, OHV (Overhead Valve)
Displacement Cc:
Typically 997cc (Ironhead Sportster 1000)
Bore X Stroke:
Approximately 3.1875 in. x 3.75 in. (81 mm x 95 mm) - verify for specific sub-models
Compression Ratio:
Typically 8.0:1 to 9.0:1 (verify for specific sub-models)
Cylinder Material:
Cast Iron
Cylinder Head Material:
Cast Iron
Horsepower Hp:
Approximately 55-65 HP (estimate, actual varies by tune and year)
Torque Lb-Ft:
Approximately 60-70 lb-ft (estimate, actual varies by tune and year)
Carburetor Type:
Single Keihin butterfly or Linkert type (depending on specific year and model variant)
Fuel Delivery:
Gravity feed from fuel tank via petcock
Type:
Battery and Coil, breaker points ignition
System:
Dry Sump (oil tank mounted separately)
Oil Capacity Quarts:
Approximately 3 quarts (verify for specific model)
Recommended Oil Type:
Viscosity typically SAE 20W-50 or 20W-40 motorcycle-specific oil. Check manual for exact specifications.
Type:
4-speed constant mesh, foot-shifted (left-foot shift)
Optional Transmissions:
N/A (4-speed was standard for this generation)
Clutch:
Wet multi-plate clutch
Primary Drive:
Primary chain drive connecting engine crankshaft to transmission input shaft
Fluid Type:
Typically SAE 50 or SAE 60 gear oil (verify manual for specific type and viscosity)
Wheelbase Inches:
Approximately 57-60 inches (varies slightly by year and model)
Length Inches:
Approximately 85-90 inches (varies by model)
Dry Weight Lbs:
Approximately 450-500 lbs (varies by model)
Gross Vehicle Weight Rating Gvwr Lbs:
Typically around 800-850 lbs (verify specific model)
Safety Ratings:
No formal crash test ratings for motorcycles of this era. Safety relies on rider skill and basic mechanical integrity.
Braking System:
Dual leading shoe front drum brake, single leading shoe rear drum brake.
Lighting:
Headlight, taillight, brake light, turn signals (if equipped).
Frame Construction:
Steel backbone frame
Infotainment Systems:
N/A. Motorcycles of this era lacked electronic infotainment systems.
Driver Assistance Features:
N/A. No electronic rider aids or driver assistance technologies were present.
Connectivity Options:
N/A. No integrated connectivity features.
Oil Change Interval:
Typically every 2,000 to 3,000 miles or annually, whichever comes first. Verify in manual.
Tune Up Interval:
Spark plugs, points, and carburetor adjustments typically every 3,000-5,000 miles.
Primary Chain Adjustment:
Check and adjust as needed, typically every 1,000-2,000 miles or as chain stretches.
Engine Oil Type:
SAE 20W-50 or 20W-40 motorcycle-specific oil with ZDDP additive recommended for older flat-tappet engines.
Transmission Oil Type:
SAE 50 or SAE 60 gear oil (verify manual).
Brake Fluid Type:
N/A (Drum brakes typically do not use hydraulic fluid).
Fork Oil Type:
Typically SAE 10W or 20W fork oil (verify manual for specific weight and capacity).
Electrical System Reliability:
Older wiring harnesses can degrade, leading to intermittent electrical problems. Generator systems can be less robust than later alternators.
Carburetor Tuning:
Linkert and early Keihin carburetors can be finicky and require regular adjustment and cleaning.
Pushrod Seals:
Leaking pushrod tube seals are common and require replacement.
Ironhead Engine Characteristics:
Can be prone to oil leaks if not meticulously maintained. 'Ironhead' engines are known for their distinctive sound and character.
Legacy:
Harley-Davidson has a long-standing reputation for American motorcycle manufacturing, established in 1903.
Sportster Lineage:
The Sportster line, introduced in 1957, is Harley-Davidson's longest-running model line. The XLH models of the 1970s represent the 'Ironhead' era, characterized by cast iron cylinders and heads.
Key Changes 1970S:
Transition from generator to alternator systems (mid-70s), evolution of brake systems, and minor styling updates.
Manufacturing Location:
Milwaukee, Wisconsin, USA
Production Period:
The Sportster XLH was produced continuously through the 1970s, with annual model variations.
Model Recognition:
The Harley-Davidson Sportster XLH 1970-1978 is a highly regarded classic motorcycle, often featured in custom builds and collector circles. It has earned a reputation for its iconic styling and raw performance.
Automotive Journal Reviews:
Contemporary reviews from publications like Cycle World and Hot Rod Magazine often praised its power and handling for the era, while also noting the specific maintenance requirements of Harley-Davidson V-twins.
Manual Certification:
This manual is an unofficial compilation of service information, not an official Harley-Davidson factory publication. Accuracy is based on industry standards and common knowledge for the period.
