Target Audience:
Owners and independent repair shops specializing in vintage Harley-Davidson motorcycles, particularly the less common SX series.
Value Proposition:
Provides essential, manufacturer-verified technical data for repairing and maintaining a specific, often overlooked, model. Crucial for preserving the originality and functionality of these classic machines.
Factory Accuracy:
Directly sourced from Harley-Davidson, ensuring the highest level of accuracy for procedures, specifications, and parts identification.
Diagnostic Focus:
Emphasis on diagnostic procedures and troubleshooting guides to efficiently resolve mechanical and electrical issues.
Engine Mechanical:
Engine disassembly, assembly, inspection, repair, and tuning for the 250cc two-stroke engine.
Fuel System:
Carburetor adjustment, cleaning, and rebuilding; fuel tank and petcock service.
Ignition System:
Ignition timing, coil testing, spark plug specifications, and related components.
Transmission Drivetrain:
Clutch operation, transmission disassembly, assembly, and adjustment; chain drive maintenance.
Electrical System:
Wiring diagrams, lighting system, battery maintenance, charging system (alternator/generator), and switchgear.
Braking System:
Front and rear brake system inspection, adjustment, and repair; drum brake components.
Suspension Steering:
Front fork service, rear shock absorber inspection, steering head bearing adjustment, and wheel bearing maintenance.
Bodywork Chassis:
Frame inspection, fender mounting, seat removal, and handlebar adjustments.
Wheels Tires:
Tire pressure recommendations, wheel balancing, and spoke tension checks.
Routine Maintenance:
Oil changes, chain lubrication, filter cleaning/replacement, spark plug checks, and general inspection.
Troubleshooting:
Diagnostic charts and common problem identification for engine, electrical, and mechanical issues.
Major Repairs:
Complete engine rebuilds, transmission overhauls, and suspension component replacements.
Adjustments:
Carburetor tuning, ignition timing, clutch and brake adjustments, and suspension setup.
Component Overhaul:
Detailed procedures for rebuilding carburetors, brake systems, and other wear components.
Depth Of Coverage:
Comprehensive, suitable for both experienced mechanics and dedicated DIY enthusiasts. Covers everything from basic checks to full engine and transmission rebuilds.
Digital Format Availability:
Typically available as a PDF; physical print versions are also common.
Print Quality:
High-resolution scans of original factory documentation, ensuring clarity of text and diagrams.
Binding Type:
Professionally bound for durability in a workshop environment (for physical copies).
Paper Type:
Durable paper stock to withstand workshop use.
Engine Type:
Two-stroke, single-cylinder
Bore X Stroke:
66 mm x 72 mm
Compression Ratio:
Approximately 7.0:1
Cooling System:
Air-cooled
Lubrication:
Pre-mix or oil injection (depending on specific market variant, manual will detail).
Horsepower:
Approximately 22-25 HP @ 6000 RPM
Torque:
Approximately 20-22 lb-ft @ 5000 RPM
Carburetor Type:
Single Mikuni VM30 (common, manual will confirm exact model).
Fuel Type:
Unleaded gasoline (premium recommended), mixed with 2-stroke oil as per specifications.
Oil Change Interval:
Typically every 1,000-1,500 miles or seasonally, depending on usage. (Manual will provide precise interval).
Spark Plug Check Interval:
Every 1,000-2,000 miles. (Manual will specify).
Chain Lubrication Interval:
Every 500 miles and after washing or riding in wet conditions. (Manual will detail).
Transmission Oil Type:
API GL-4 80W-90 gear oil (typical, manual to confirm exact specification).
2 Stroke Oil Mix:
Specific ratio (e.g., 20:1 or 32:1) and oil type (e.g., API TC, JASO FD) will be detailed in the manual.
Carburetor Tuning:
Mikuni carburetors can be sensitive to altitude and humidity; requires precise tuning for optimal performance. Manual provides tuning guides.
Ignition Timing:
Proper ignition timing is critical for two-stroke engines; manual details the procedure and specifications.
Wear Components:
Due to age, wear on clutch plates, brake shoes, and suspension bushings is common. Manual covers their inspection and replacement.
Harley Davidson Legacy:
Harley-Davidson, a storied American manufacturer, known for its V-twin cruisers, but also explored different segments with models like the SX series.
Sx Series Context:
The SX series, particularly the SX 250, was Harley-Davidson's foray into the burgeoning off-road and dual-sport market of the 1970s. It shared some components and design philosophies with Italian Aermacchi motorcycles, which Harley-Davidson had a stake in.
Production Period:
The SX 250 was produced primarily in the mid-1970s (e.g., 1974-1977), with the 1975 model being a significant year in its limited production run.
Manufacturing Origin:
Often assembled in the USA utilizing components or designs influenced by Aermacchi in Italy.
