Historical Market Segment:
The Yamaha SR250 Exciter was positioned as an entry-level to mid-range versatile motorcycle, often appealing to commuters and riders seeking a balance of performance and economy in its era.
Key Competitors 1981:
Competed with other Japanese manufacturers' 250cc offerings, such as Honda's CB250 series, Kawasaki's KZ250, and Suzuki's GS250E.
Defining Characteristics:
Known for its reliable single-cylinder engine, comfortable riding posture, and utilitarian design, making it a practical choice for daily use.
Primary Coverage:
All components and sub-assemblies of the Yamaha SR250H Exciter motorcycle for the 1981 model year.
Component Groupings:
Engine, carburetor, fuel system, transmission, chassis, suspension (front and rear), wheels, brakes, electrical system, ignition, lighting, bodywork, controls, exhaust system, and accessories.
Estimated Page Count:
Variable, typically between 80-150 pages for this era of parts manual, dependent on specific diagram detail and part number listings.
Manual Category:
Parts Catalog / Parts Manual
Manual Function:
Identification and ordering of genuine Yamaha replacement parts.
Engine Mechanical:
Cylinder, piston, crankshaft, connecting rod, valves, camshaft, timing components, oil pump, and associated seals and gaskets.
Fuel Delivery:
Carburetor assembly (Mikuni VM series likely), fuel tank, petcock, fuel lines, and filters.
Ignition System:
CDI unit, ignition coil, spark plug, stator, and wiring harness components.
Transmission And Drivetrain:
Gearbox internals (shifter drum, gears, shafts), clutch assembly, primary drive, and rear chain drive components.
Chassis And Frame:
Frame sections, swingarm, engine mounts, and associated hardware.
Suspension Front:
Front fork tubes, stanchions, springs, seals, dampers, triple clamps, and steering head bearings.
Suspension Rear:
Rear shock absorber(s), swingarm bushings, and linkage components (if applicable).
Braking System:
Front and rear brake calipers, master cylinders, brake lines, brake pads, brake discs/drums, and associated hardware.
Wheels And Tires:
Wheel rims, spokes, hubs, bearings, tire specifications, and valve stems.
Electrical Lighting:
Headlight, taillight, turn signals, instrument cluster illumination, wiring harnesses, connectors, fuses, and battery terminals.
Bodywork And Trim:
Fuel tank, side covers, fenders, seat, emblems, and fasteners.
Controls And Linkages:
Handlebars, levers (clutch, brake), throttle assembly, footpegs, gear shift lever, and brake pedal linkage.
Exhaust System:
Exhaust header pipes, muffler, mounting brackets, and gaskets.
Identification Of Parts:
Detailed exploded diagrams allowing visual identification of all components and their relationship to each other.
Part Number Reference:
Comprehensive listing of Yamaha part numbers for each individual component, essential for accurate ordering.
Assembly Guidance:
Implicit guidance for correct assembly through exploded views and part relationships.
Disassembly Guidance:
Implicit guidance for disassembly by illustrating component removal sequences.
Depth Of Coverage:
Component-level identification and part number referencing. Does not include detailed repair procedures or torque specifications, which are found in a service manual.
Engine Type:
4-stroke, SOHC, air-cooled, single-cylinder
Displacement:
249 cc (approx. 15.2 cubic inches)
Bore X Stroke:
Approximately 69.0 mm x 68.6 mm (exact figures may vary slightly by sub-model or region)
Horsepower Estimate:
Around 19-23 hp at 7500-8000 RPM (specific figure dependent on tuning and region)
Torque Estimate:
Around 19-21 Nm (14-15 lb-ft) at 6000 RPM (specific figure dependent on tuning and region)
Carburetor Type:
Single Mikuni VM Series carburetor (e.g., VM28 or similar)
Fuel Capacity Estimate:
Approximately 12-14 liters (3.2-3.7 US gallons)
Oil Capacity Estimate:
Around 1.5-1.8 liters (1.6-1.9 US quarts), including oil filter
Engine Family Code:
Typically starts with '4E0' or similar, specific to Yamaha's engine designation system.
Overall Length Estimate:
Approximately 2050 mm (80.7 inches)
Overall Width Estimate:
Approximately 820 mm (32.3 inches)
Overall Height Estimate:
Approximately 1130 mm (44.5 inches)
Dry Weight Estimate:
Around 130-135 kg (287-298 lbs)
Wet Weight Estimate:
Around 145-150 kg (320-331 lbs), with all fluids
Front Wheel Size:
18-inch
Front Tire Size Recommendation:
e.g., 3.00-18
Rear Tire Size Recommendation:
e.g., 100/90-17
Oil Change Interval Estimate:
Recommended every 3,000-5,000 km (1,800-3,000 miles) or annually, whichever comes first.
Air Filter Cleaning Interval Estimate:
Recommended every 3,000-6,000 km (1,800-3,700 miles), depending on operating conditions.
Spark Plug Replacement Interval Estimate:
Recommended every 6,000-10,000 km (3,700-6,000 miles).
Valve Clearance Check Interval Estimate:
Recommended every 10,000-15,000 km (6,000-9,000 miles).
Engine Oil Type Recommendation:
API SE or SF grade, SAE 10W-40 or 20W-50 motorcycle-specific oil.
Fork Oil Type Recommendation:
Typically SAE 10W fork oil.
Common Wear Items:
Carburetor jets can clog with age, clutch plates can wear, brake components (seals, pads) require regular inspection, and fork seals may leak.
Electrical Considerations:
Wiring harness connectors can corrode over time, affecting electrical component function.
Carburetor Tuning:
Due to age, carburetor tuning may require frequent adjustments or a rebuild with new gaskets and O-rings.
Yamaha Motorcycles:
Yamaha Motor Corporation, founded in 1955, has a rich history in motorcycles, leveraging its expertise in engine design and manufacturing from its musical instrument and other industrial divisions.
Sr Series Lineage:
The SR series, particularly the SR400 and SR500, are legendary for their simple, robust single-cylinder designs. The SR250 was introduced as a more accessible, smaller-displacement option within this family, offering similar classic styling and reliable performance.
Production Years:
The SR250 model line saw production across several years, with the 'Exciter' designation often used for specific regional variants or updates. The 1981 model is part of the early production run.