Segment:
Entry-level to intermediate off-road motorcycle, popular for youth motocross, trail riding, and general recreational use.
Competitors:
Honda CR80, Yamaha YZ80, Suzuki RM80.
Vehicle Attributes:
Lightweight, user-friendly, durable, simple maintenance, reliable 2-stroke engine.
Value Proposition:
Essential resource for owners to maintain, repair, and troubleshoot their KDX 80, ensuring longevity and optimal performance.
Engine Mechanical:
Full overhaul, top-end rebuild, bottom-end rebuild, valve timing, piston/ring replacement, cylinder boring.
Engine Tuning:
Carburetor adjustment, ignition timing, compression testing, exhaust system diagnostics.
Fuel System:
Carburetor disassembly, cleaning, rebuilding, fuel line inspection, fuel tank maintenance.
Transmission Drivetrain:
Clutch operation, gear selection, gearbox disassembly, assembly, lubrication, final drive (chain/sprockets).
Suspension:
Front fork service (oil change, seal replacement, spring inspection), rear shock absorber inspection and replacement, linkage lubrication.
Brakes:
Drum brake inspection and adjustment, brake shoe replacement, brake cable maintenance.
Electrical System:
Ignition system (CDI, spark plug, coil), lighting system (headlight, taillight, brake light), wiring diagrams, battery maintenance.
Cooling System:
Air-cooled engine, focus on cylinder head cooling fins and proper airflow.
Frame Bodywork:
Frame inspection, handle bar replacement, seat maintenance, fender and plastic trim repair/replacement.
Routine Maintenance:
Oil changes, filter cleaning/replacement, chain adjustment, lubrication points, pre-ride checks.
Troubleshooting:
Diagnostic flowcharts for common problems (starting issues, poor performance, electrical faults).
Repair Procedures:
Step-by-step instructions for component removal, installation, and rebuilding.
Specifications:
Torque values, clearances, fluid capacities, electrical resistance values.
Special Tools:
Identification and usage of specialized tools required for certain procedures.
Depth:
Comprehensive; covers everything from basic maintenance to full engine and transmission rebuilds. Suitable for home mechanics and professional technicians.
Engine Type:
2-stroke, single-cylinder, reed-valve induction
Displacement:
79 cc (4.82 cu in)
Bore X Stroke:
48.0 x 44.0 mm
Cooling System:
Air-cooled
Compression Ratio:
Typically around 7.0:1 (varies slightly by year/spec)
Horsepower:
Approximately 10-12 HP (actual figures vary by year and tuning)
Torque:
Estimated 5-7 lb-ft (actual figures vary)
Carburetor Model:
Mikuni VM series (e.g., VM20 or VM22, specific size varies)
Fuel Type:
Unleaded gasoline (typically 87 octane or higher)
Fuel Mixture:
Premix (typically 32:1 or 40:1 ratio of gasoline to 2-stroke oil)
2-Stroke Oil Type:
High-quality 2-stroke motorcycle oil (API TC, JASO FD compliant recommended)
Length:
Approx. 1750-1800 mm (varies slightly by year)
Width:
Approx. 770-800 mm (varies slightly by year)
Height:
Approx. 1050-1100 mm (varies slightly by year)
Dry Weight:
Approx. 70-75 kg (154-165 lbs)
Fuel Capacity:
Approx. 5.5 - 6.5 liters (1.45 - 1.72 US gallons)
Wheelbase:
Approx. 1220-1240 mm (48.0-48.8 in)
Crash Test Ratings:
Not applicable (off-road motorcycle)
Braking System:
Front: Drum; Rear: Drum
Suspension Type:
Front: Telescopic fork; Rear: Swingarm with monoshock or twin shocks (depending on exact year/model variant)
Lighting:
Headlight, taillight, brake light, turn signals may be optional or present depending on market/trim.
Handlebar Design:
Standard motocross/off-road handlebars for control and maneuverability.
Oil Change:
Every 10-15 engine hours or annually. Manual specifies precise interval.
Spark Plug Replacement:
Check every 10-15 hours, replace as needed. Manual will specify gap and type (e.g., NGK B8ES).
Air Filter Cleaning:
Every 5-10 hours, or more frequently in dusty conditions. Manual details cleaning and oiling procedure.
Chain Lubrication Adjustment:
Lubricate every 5-10 hours, adjust tension every 15-20 hours. Manual specifies correct slack.
Fork Oil Change:
Recommended every 12-24 months or 200-300 hours. Manual specifies oil type and quantity.
Transmission Oil Spec:
SAE 80 or SAE 90 hypoid gear oil. Check manual for exact API classification.
Fork Oil Spec:
Typically SAE 10W or SAE 15W fork oil. Manual will provide exact viscosity and capacity.
Brake Fluid Type:
DOT 3 or DOT 4 (if hydraulic brakes were ever an option, though unlikely for 80cc drum brakes). Manual will clarify.
Common Wear Items:
Clutch plates, wheel bearings, steering bearings, swingarm bushings, chain and sprockets, fork seals, exhaust packing.
Engine Performance Issues:
Carburetor gumming, fouled spark plugs, worn piston rings, exhaust port carbon buildup.
Electrical Issues:
Loose connections, aging wiring, CDI unit failure, stator issues (less common).
Manufacturer:
Kawasaki Heavy Industries Motorcycle & Engine Company, a globally recognized leader in motorcycle manufacturing.
Kdx Lineage:
The KDX series has a long history in off-road racing and trail riding, known for its performance and durability. The KDX 80 represents the entry-level displacement within this lineage.
Manufacturing Era:
Produced throughout the 1980s, this model was a staple for young riders entering the sport.
