Historical Context:
The SX 250 was Harley-Davidson's foray into the burgeoning off-road and trail bike market, a segment often dominated by European and Japanese manufacturers. It represented an effort to broaden their appeal beyond traditional cruiser motorcycles.
Rivals:
Competed against models like the Yamaha DT series, Suzuki TS series, Honda CR and SL series, and European off-road bikes from manufacturers like Husqvarna and Ossa. It was designed to offer a more rugged, American-built option in this category.
Uniqueness:
Distinguished by its Harley-Davidson heritage in a typically non-Harley segment, a robust 2-stroke engine, and an emphasis on durability for trail use. It offered a distinct character compared to its contemporaries.
Target User:
Ideal for Harley-Davidson SX 250 owners, mechanics, restorers, and enthusiasts looking to perform maintenance, repairs, or understand the technical intricacies of this specific model.
Benefits:
Provides authoritative, manufacturer-backed procedures and specifications, ensuring correct repairs and adjustments, vital for preserving the originality and functionality of a vintage motorcycle.
Primary Focus:
Comprehensive service, repair, and maintenance for the 1976 Harley-Davidson SX 250
Estimated Pages:
N/A (often available as digital PDF, actual page count varies by source/format)
Type:
Factory Service Repair Manual
Format:
Digital PDF (typical for modern reissues)
Engine:
2-stroke piston port single cylinder engine, cylinder head, cylinder, piston, connecting rod, crankshaft, crankcase, lubrication, cooling (air-cooled)
Fuel System:
Carburetor (likely AMAL), fuel tank, fuel lines, fuel filter
Ignition System:
Contact breaker points ignition, coil, spark plug, timing
Transmission:
4-speed constant mesh, clutch, gearbox disassembly and assembly, shift mechanism
Frame And Suspension:
Frame construction, front forks (telescopic), rear shock absorbers, swingarm, steering head bearings
Brakes:
Front drum brake, rear drum brake, brake linkages and adjustments
Wheels And Tires:
Spoked wheels, hub maintenance, bearing replacement, tire specifications and pressures
Electrical System:
Lighting system (headlight, taillight, indicators), charging system (if applicable, often generator on vintage bikes), wiring diagrams, battery maintenance
Bodywork:
Fuel tank, seat, fenders, side covers, instrument cluster removal and installation
Maintenance:
Routine checks, lubrication, filter changes, spark plug replacement, chain adjustment
Repair:
Engine rebuilds, transmission overhauls, suspension component replacement, brake system repairs, electrical troubleshooting
Disassembly And Assembly:
Step-by-step instructions for removing and reinstalling major components and sub-assemblies
Troubleshooting:
Diagnosis of common problems and their solutions, based on symptoms
Adjustments:
Carburetor tuning, ignition timing, clutch and brake lever adjustments, chain slack
Depth:
Comprehensive (covers basic maintenance to complete engine and transmission rebuilds)
Type:
Two-stroke, air-cooled, single-cylinder
Displacement:
247 cc (approx.)
Bore X Stroke:
70 mm x 64 mm (typical for this displacement range)
Compression Ratio:
Approximately 7.0:1 (typical for 2-stroke of this era)
Horsepower:
Approx. 20-25 HP @ 6000 RPM (estimated based on similar displacement 2-strokes of the era)
Torque:
N/A (Specific torque figures are rarely published for vintage 2-stroke dirt bikes)
Carburetor Type:
Likely AMAL Monobloc or concentric (e.g., AMAL 276 or similar)
Carburetor Size:
Typically 26mm or 28mm for this displacement
Fuel Type:
Leaded gasoline with 2-stroke oil mixture (e.g., 20:1 or 25:1 ratio)
Type:
Premix in fuel tank
Type:
Contact breaker points with flywheel magneto (typical for vintage Harley-Davidson motorcycles)
Spark Plug Type:
NGK B8ES or Champion L77C (example, check manual for exact spec)
Type:
4-speed, constant mesh, sequential gearbox
Variants:
N/A (Single transmission option typically)
Clutch Type:
Wet multi-plate
Gear Ratios:
N/A (Specific ratios not readily available, but detailed in manual)
Gearbox Oil:
SAE 80W or 90W gear oil (check manual for precise specification)
Crash Test Results:
N/A (Motorcycle safety ratings were not standardized in 1976 as they are for modern cars)
Braking System:
Dual leading shoe drum brakes front and rear. Focus on proper adjustment and maintenance of brake cables and shoes.
Lighting:
Headlight, taillight, and potentially brake light and turn signals (depending on specific market configuration). Manual covers electrical system checks and bulb replacement.
Oil Change Frequency:
Gearbox oil change: Every 3,000-5,000 miles or annually. Transmission fluid specification: SAE 80W or 90W.
Spark Plug Replacement:
Inspect and clean every 1,000-2,000 miles, replace as needed based on condition.
Chain Maintenance:
Lubricate and adjust chain slack every 500-1,000 miles or after riding in wet conditions.
Air Filter Cleaning:
Clean and re-oil foam element every 1,000-2,000 miles or more frequently in dusty conditions.
Fuel Mixture:
2-stroke oil to gasoline ratio of 20:1 or 25:1 (refer to manual for exact recommendation, use high-quality 2-stroke oil).
Fork Oil:
Typically SAE 10W or 15W fork oil. Capacity: Check manual for specific amount per fork leg.
Carburetor Tuning:
Carburetors (especially older AMAL units) can be finicky and require frequent adjustment for optimal performance and starting, particularly with modern fuel blends.
Electrical Reliability:
As with many vintage motorcycles, the electrical system, particularly the ignition components and wiring, can be prone to issues due to age and oxidation. The manual is crucial for troubleshooting.
Engine Seals:
Leaking crankcase seals are a common issue on vintage 2-strokes, leading to air leaks and poor running. The manual details seal replacement procedures.
Clutch Slipping:
Worn clutch plates or improper cable adjustment can lead to clutch slipping. The manual provides inspection and adjustment procedures.
Legacy:
Harley-Davidson, established in 1903, is renowned for its V-twin cruisers and heavyweight motorcycles. The SX 250 represented a brief but significant diversification into the off-road segment, leveraging their manufacturing expertise.
Development:
The SX 250 was part of Harley-Davidson's effort in the 1970s to compete in more diverse market segments. It was developed alongside the larger SX 125 and SX 250 models to capture the growing interest in trail riding and motocross.
Production Years:
1974-1978 (approximate for the SX 250 model line)
Manufacturing Location:
York, Pennsylvania, USA (Harley-Davidson's primary manufacturing facility)
Historical Accolades:
While the SX 250 itself may not have specific widely publicized awards from its production era, it represents Harley-Davidson's successful, albeit short-lived, expansion into a competitive market segment. Its value lies in its historical significance as part of the brand's diverse product portfolio.
Performance Reviews:
Contemporary reviews often noted its rugged construction and capable off-road performance for its displacement, although comparisons to specialized European competition would have highlighted differences in handling and outright performance.
