Target Audience:
Owners seeking to perform their own maintenance and repairs, independent motorcycle workshops
Vehicle Segment:
Lightweight/Commuter Motorcycle
Competitors 80S:
Honda CB250, Yamaha SR250, Kawasaki EN450 (similar displacement/class)
Engine Type:
Reliable, torquey single-cylinder engine known for its longevity
Design Philosophy:
Simple, robust, and user-friendly design prioritizing practicality and ease of maintenance
Engine Mechanical:
Complete engine disassembly, inspection, and reassembly (cylinder head, piston, crankshaft, valve train, timing chain)
Engine Fuel System:
Carburetor overhaul, tuning, fuel delivery system, fuel tank, fuel lines
Ignition System:
Ignition timing, coil, spark plug, CDI unit troubleshooting
Cooling System:
Air-cooled engine thermal management, heat dissipation
Transmission:
Gearbox disassembly, inspection, and reassembly, clutch operation and adjustment
Drivetrain:
Final drive (chain and sprockets) inspection and maintenance
Suspension:
Front fork service (oil change, seal replacement), rear shock absorber maintenance
Brakes:
Front and rear brake system maintenance (drum brakes), hydraulic component inspection (if applicable for later models, though GN250 is primarily drum), fluid replacement
Electrical System:
Wiring diagrams, lighting system, starter motor, charging system (alternator/stator, rectifier/regulator), battery maintenance
Chassis And Frame:
Frame inspection, steering head bearing maintenance
Bodywork And Trim:
Panel removal and installation, seat, tank, fenders
Routine Maintenance:
Oil changes, filter replacements, chain adjustment, spark plug checks, air filter cleaning/replacement
Troubleshooting:
Diagnostic procedures for common engine, electrical, and mechanical issues
Major Repairs:
Engine rebuild, transmission overhauls, suspension overhauls, electrical system diagnostics
Specifications And Tolerances:
Detailed torque specifications, clearances, and measurement data
Component Removal Installation:
Step-by-step guides for removing and reinstalling all major components
Depth:
Comprehensive (suitable for amateur mechanics to professional technicians)
Diagnostic Capabilities:
Detailed diagnostic flowcharts and symptom-based troubleshooting guides
Rebuild Guidance:
Complete engine and transmission rebuild procedures with diagrams and tolerances
Digital Format:
PDF (Portable Document Format)
Searchability:
Searchable text for quick information retrieval
Printability:
Printable pages for on-site workshop use
Image Resolution:
High-resolution images and diagrams
Diagram Clarity:
Clear, detailed exploded views and schematic diagrams
Digital Format Binding:
N/A (Digital)
Digital Format Paper:
N/A (Digital)
Engine Type:
Four-stroke, single-cylinder, SOHC
Displacement:
249 cc (15.2 cu in)
Bore X Stroke:
72.0 mm x 61.2 mm (2.83 in x 2.41 in)
Cooling System:
Air-cooled
Horsepower Peak:
Approx. 21 hp @ 7,500 rpm (varies slightly by market/tune)
Torque Peak:
Approx. 20 Nm (14.8 lb-ft) @ 6,000 rpm (varies slightly)
Carburetor Type:
Mikuni VM26SS (or similar single Mikuni carburetor)
Fuel Capacity:
13.0 L (3.4 US gal)
Fuel Type:
Unleaded gasoline, 87 octane minimum
Overall Length:
Approx. 2,135 mm (84.1 in)
Overall Width:
Approx. 820 mm (32.3 in)
Overall Height:
Approx. 1,110 mm (43.7 in)
Wheelbase:
Approx. 1,415 mm (55.7 in)
Dry Weight:
Approx. 140 kg (309 lbs)
Wet Weight:
Approx. 150 kg (331 lbs) (fully fueled, oil, etc.)
Safety Standards:
Meets or exceeds regulatory requirements for its era in relevant markets (e.g., EPA, DOT considerations for emissions/lighting).
Braking System:
Front: Drum brake. Rear: Drum brake. (Note: Some later variants might have seen disc brake applications, but 82-83 are typically drum front and rear).
Suspension Stability:
Telescopic front fork and adjustable rear suspension provide adequate stability for its class.
Oil Change Interval:
Every 3,000 - 5,000 km (1,800 - 3,000 miles) or annually, whichever comes first.
Air Filter Cleaning:
Inspect every 3,000 km (1,800 miles), clean or replace as needed. Replacement recommended every 6,000 - 10,000 km (3,700 - 6,000 miles).
Spark Plug Replacement:
Replace every 6,000 - 10,000 km (3,700 - 6,000 miles). Check gap annually.
Chain Lubrication Adjustment:
Lubricate chain every 1,000 km (600 miles) or after riding in rain. Adjust tension every 3,000 km (1,800 miles).
Engine Oil Type:
SAE 10W-40 API SG or higher motorcycle-specific oil.
Engine Oil Capacity:
Approx. 1.8 L (1.9 US qt) with filter change; 1.6 L (1.7 US qt) without filter change.
Fork Oil Type:
SAE 10W fork oil
Fork Oil Capacity:
Approx. 190-200 cc per fork leg (check manual for exact specification)
Carburetor Issues:
Mikuni carburetors can sometimes suffer from clogged jets due to fuel varnish or debris, especially if the bike sits for extended periods. Proper cleaning and rebuilding are key.
Starter Clutch Wear:
Some models may experience wear on the starter clutch mechanism, leading to a grinding noise or failure to engage the starter motor.
Electrical Connections:
Corrosion or looseness in electrical connectors can lead to intermittent electrical issues. Regular inspection and cleaning are recommended.
Valve Clearance:
Valve clearances need periodic adjustment to maintain engine performance and prevent damage. This is a common maintenance item for this era of motorcycle.
Suzuki Motorcycle Legacy:
Suzuki has a long history of producing reliable and innovative motorcycles, from small displacement commuters to powerful sportbikes and cruisers.
Gn Series Introduction:
The GN series was introduced in the early 1980s as Suzuki's entry into the popular lightweight commuter/cruiser market, emphasizing classic styling and user-friendliness.
Gn250 Significance:
The GN250 established Suzuki's reputation for producing robust single-cylinder engines, becoming a common sight in urban environments for its economy and reliability.
Production Period:
The GN250 was produced from the early 1980s through the early 2000s in various forms and markets.
Manufacturing Origin:
Primarily Japan
