This document is an Owner's Service Manual for the Yamaha TT-R125E(R) and TT-R125LWE(R) off-road motorcycles, published in November 2002. It provides comprehensive information on operation, inspection, basic maintenance, and tuning.
Function Description:
The Yamaha TT-R125E(R) and TT-R125LWE(R) are off-road motorcycles designed for young operators under adult instruction and supervision. They are not suitable for on-road use. The motorcycles feature a constant-mesh 5-speed transmission, allowing for varied speed ranges suitable for off-road conditions. Starting is achieved via kick and electric starter.
Important Technical Specifications:
General Specifications (TT-R125E):
- Engine Type: Air-cooled 4-stroke, SOHC, single cylinder, forward inclined.
- Displacement: 124 cm³ (7.57 cu.in).
- Bore × Stroke: 54.0 × 54.0 mm (2.126 × 2.126 in).
- Compression Ratio: 10.0:1.
- Starting System: Kick and electric starter.
- Lubrication System: Wet sump.
- Recommended Engine Oil: Yamalube 4 (10W-30) or SAE 10W-30 type SE motor oil (for temperatures at -10°C (10°F) or higher), or Yamalube 4 (20W-40) or SAE 20W-40 type SE motor oil (for temperatures at 5°C (40°F) or higher). API "SE" or higher grade (except for USA and CDN).
- Oil Capacity: 1.0 L (0.88 Imp qt, 1.06 US qt) for periodic oil change; 1.2 L (1.06 Imp qt, 1.27 US qt) total amount.
- Fuel Type: Unleaded gasoline only (USA, AUS, NZ); Regular unleaded gasoline only (CDN, EUROPE); Regular gasoline (ZA).
- Fuel Tank Capacity: 6.6 L (1.45 Imp gal, 1.74 US gal) total; 1.9 L (0.42 Imp gal, 0.5 US gal) reserve.
- Carburetor: MIKUNI VM20SS.
- Spark Plug: NGK/DENSO CR7HSA/U22FSR-U, gap 0.6 ~ 0.7 mm (0.02 ~ 0.03 in).
- Clutch Type: Wet, multiple-disc.
- Transmission: Constant mesh, 5-speed, left foot operation.
- Frame Type: Diamond.
- Caster Angle: 28.7°.
- Trail: 93 mm (3.66 in).
- Tires: With tube. Front: 70/100-17 40M; Rear: 90/100-14 49M. Pressure: 100 kPa (1.00 kgf/cm², 15 psi).
- Brakes: Drum brake (front and rear).
- Suspension: Telescopic fork front, Swingarm (link type monocross suspension) rear.
- Wheel Travel: 180 mm (7.09 in) front, 160 mm (6.30 in) rear.
- Electrical: CDI ignition system, CDI magneto generator, GT4L-BS 12 V/3.2 AH battery.
General Specifications (TT-R125LWE):
- Overall Length: 1,885 mm (74.2 in) compared to 1,830 mm (72.0 in) for TT-R125E.
- Overall Width: 795 mm (31.3 in).
- Overall Height: 1,085 mm (42.7 in).
- Seat Height: 805 mm (31.7 in).
- Wheelbase: 1,270 mm (50.0 in).
- Minimum Ground Clearance: 295 mm (11.6 in).
- Tires: Front: 70/100-19 42M; Rear: 90/100-16 52M.
- Front Brake Type: Single disc brake.
- Rear Wheel Travel: 168 mm (6.61 in).
Other engine and electrical specifications are largely similar to the TT-R125E.
Usage Features:
- Control Functions: Includes clutch lever, engine stop switch, main switch, starter knob (choke), start switch, front brake lever, throttle grip, rear brake pedal, fuel cock (ON/OFF/RES positions), fuel tank cap, and sidestand.
- Starting Procedure (Cold Engine): Shift to neutral, turn fuel cock to "ON" and open starter knob (choke) fully, turn main switch to "ON", start engine with start switch or kickstarter, warm up engine for 1-2 minutes until it responds normally to throttle with choke off.
- Starting Procedure (Warm Engine): Do not use starter knob (choke), open throttle slightly, and use kickstarter.
- Break-in Period: Avoid full-throttle operation for the first 5 hours. After break-in, check for loose parts, oil leakage, slack cables, drive chain, and loose spokes.
- Safety Information: Emphasizes reading the manual, adult supervision, wearing protective gear (helmet, goggles, mouth guard, gloves, boots, motocross pants, long-sleeved trainer, protector), not exceeding rider weight (68 kg/150 lb for TT-R125E), avoiding hot/moving parts, and off-road use only.
Maintenance Features:
- Maintenance Intervals: A schedule for checks and maintenance jobs, including initial (10 hours/1 month) and every (60 hours/6 months, 120 hours/12 months) intervals. Items include fuel line, spark plug, valves, air filter, carburetor, exhaust systems, engine oil, clutch, brakes, wheels, tires, wheel bearings, swingarm, drive chain, steering bearings, and sidestand.
- Pre-Operation Inspection: A checklist of items to verify before each ride, such as fuel, engine oil level, gear shifter and clutch operation, throttle grip, brakes, drive chain, wheels, steering, front forks and rear shock absorber, cables, muffler, sprocket, lubrication, bolts and nuts, and lead connectors.
- Special Tools: A list of specialized tools required for accurate tune-up and assembly, with part numbers and illustrations.
- Engine Maintenance: Detailed procedures for valve clearance inspection and adjustment, air filter cleaning, engine oil level inspection and replacement, oil pressure inspection, pilot air screw adjustment, and engine idling speed adjustment.
- Chassis Maintenance: Procedures for brake system air bleeding, front brake adjustment, rear brake adjustment, brake pedal height adjustment, front brake pad inspection and replacement, rear brake shoe inspection, sprockets inspection, drive chain slack adjustment, front fork inspection and spring preload adjustment, wheel inspection, spokes inspection and tightening, steering head inspection and adjustment, and swingarm disassembly and assembly.
- Electrical Maintenance: Inspection steps for the ignition system (spark gap, couplers, main switch, engine stop switch, ignition coil, CDI magneto), electric starting system (starter motor, starting circuit cut-off relay, neutral switch, clutch switch, start switch), and charging system (fuse, battery, charging voltage, charging coil resistance). Battery inspection and charging instructions are also provided, with warnings against improper charging practices.
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