Vehicle Segment:
Entry-level to intermediate off-road/trail motorcycle.
Target Audience:
Beginner riders, youth riders, recreational trail riders seeking a reliable and manageable off-road experience.
Competitors:
Honda CRF100F/XR100R, Kawasaki KLX110/KLX125, Suzuki DR-Z110/DR-Z125.
Durability:
Yamaha's reputation for robust and reliable components, designed for the rigors of off-road use.
Versatility:
Suitable for trail riding, play riding, and novice competition due to its manageable power and size.
Ease Of Use:
User-friendly design, particularly for riders transitioning from smaller displacement or automatic transmissions.
Engine:
Detailed breakdown of the 125cc engine, including top-end, bottom-end, valve timing, piston/ring inspection, cylinder hone, crankshaft balancing, and component torque specifications.
Fuel System:
Carburetor (likely Mikuni VM series) disassembly, cleaning, adjustment, jetting recommendations, fuel filter replacement, and fuel tank inspection.
Lubrication:
Oil change procedures, oil filter replacement (if applicable), oil pump inspection and testing, oil passage cleaning, and oil pressure specifications.
Cooling System:
Air-cooled engine design, heat dissipation, cylinder head fin cleaning, and any relevant heat management components.
Ignition System:
CDI ignition system, spark plug type and gap, ignition timing specifications, stator coil testing, and troubleshooting ignition faults.
Transmission:
Clutch assembly (friction plates, steel plates, springs), gearbox disassembly and reassembly, shift drum and fork inspection, gear ratio details, and transmission oil specifications.
Brakes:
Front and rear brake systems (likely drum or disc depending on LWE variant), brake pad/shoe inspection and replacement, brake fluid type, bleeding procedures, and caliper/master cylinder servicing.
Suspension:
Front telescopic forks (including oil type, level, and seal replacement), rear monoshock or twin shock absorber system, spring preload adjustment, and damping characteristics.
Electrical System:
Wiring diagrams, battery specifications, charging system (stator, regulator/rectifier), lighting circuits (headlight, taillight, indicators), horn, and starter system (if electric start variant).
Chassis And Frame:
Frame inspection for cracks or damage, steering head bearing maintenance, swingarm bearing lubrication, and wheel bearing service.
Bodywork And Trim:
Fender removal and installation, seat, fuel tank (if applicable), plastics, and any associated trim pieces.
Maintenance:
Routine maintenance tasks such as oil changes, filter replacements, chain adjustment, spark plug checks, and air filter cleaning.
Troubleshooting:
Diagnostic flowcharts and common problem/solution guides for engine performance, electrical issues, starting problems, and braking irregularities.
Repair:
Step-by-step instructions for component disassembly, overhaul, reassembly, and adjustment for all major vehicle systems.
Diagnostics:
Guidance on identifying the root cause of malfunctions using visual inspection, sound analysis, and basic electrical testing (multimeter use).
Wiring Diagrams:
Comprehensive electrical schematics illustrating all circuits, components, and wire colors for easy troubleshooting.
Depth:
Comprehensive, suitable for professional technicians and advanced DIY mechanics. Covers everything from routine maintenance to complete engine rebuilds and electrical system diagnostics.
Engine Type:
Four-stroke, SOHC, air-cooled
Bore X Stroke:
54 mm x 54.5 mm
Compression Ratio:
9.5:1 (typical for this generation)
Horsepower:
Approx. 11-13 HP (estimated, specific figures not always published for this class)
Carburetor Type:
Mikuni VM20SS (or similar 20mm constant velocity carburetor)
Fuel Type:
Unleaded gasoline
Ignition System:
CDI (Capacitor Discharge Ignition)
Oil Type:
Yamalube 4 (or equivalent SAE 10W-40 API SG or higher motorcycle oil)
Oil Capacity:
Approx. 1.0 L (1.1 US qt) without filter change, 1.1 L (1.2 US qt) with filter change.
Transmission Type:
Constant Mesh 5-speed
Clutch Type:
Wet, multi-plate
Final Drive:
Chain drive (RK or similar, 428 pitch recommended)
Gear Ratios:
Typically: 1st: 2.833, 2nd: 1.750, 3rd: 1.333, 4th: 1.091, 5th: 0.917 (specific ratios can be found in the manual)
Transmission Oil Type:
Yamalube 4 (or equivalent SAE 10W-40 API SG or higher motorcycle oil)
Transmission Oil Capacity:
Approx. 0.65 L (0.69 US qt)
Oil Change:
Every 1000 km (600 miles) or 6 months, whichever comes first. More frequent changes recommended for hard use.
Air Filter Cleaning:
Every 500 km (300 miles) or as needed based on riding conditions. Service more frequently in dusty environments.
Spark Plug Check:
Every 1000 km (600 miles).
Chain Adjustment:
Every 500 km (300 miles) or as needed. Lubricate chain every 200 km (120 miles).
Valve Clearance Check:
Every 6000 km (3700 miles) or 24 months.
Brake Fluid:
DOT 3 or DOT 4 (refer to specific reservoir markings for confirmation).
Fork Oil:
Yamaha Suspension Oil (or equivalent SAE 10W fork oil). Capacity typically 380cc per fork leg.
Carburetor Clogging:
Common in carbureted motorcycles with infrequent use or poor fuel quality. Regular cleaning and proper storage are key.
Clutch Wear:
Friction plates can wear over time, leading to slippage. Replacement is straightforward with the manual's guidance.
Chain And Sprockets:
Wear is normal with off-road use; regular adjustment, lubrication, and timely replacement are crucial for drivetrain longevity.
