2001 Yamaha XQ125 / XQ150 Scooter Service Manual (P/N 5HT1-AE2)

The 2001 Yamaha XQ125 and XQ150 service manual (P/N 5HT1-AE2) covers maintenance, engine overhaul, chassis repair and electrical troubleshooting. Published by MBK Industrie, this English-language second edition is dated April 2001.

Searchable PDF, Chapter Bookmarks and Diagram Detail

Search and wiring detail: The PDF supports text search and has embedded bookmarks for all nine chapters plus the final wiring diagram. Small wire-color codes and connector labels in the circuit diagrams require zooming.

Supplied as one printable, 278-page PDF, including six front-matter pages, nine chapter-divider pages and one final wiring-diagram page.

Engine Overhaul, Belt-Drive Service and Fault Diagnosis

These selected coverage highlights outline the main workshop areas. Other topics include oil-indicator resetting and odometer/tripmeter settings.

• Engine overhaul: Engine removal, camshaft and rocker-arm inspection, cylinder-head service, valve work, piston measurement, crankcase separation and crankshaft checks.

• Belt drive and clutch: Primary and secondary sheave disassembly, weight inspection, clutch-shoe and housing checks, V-belt replacement and final-drive gear removal.

• Carburetor and autochoke: Carburetor disassembly and assembly, fuel-level adjustment, diaphragm and jet inspection, autochoke testing and fuel-cock checks.

• Cooling system: Radiator removal and inspection, thermostat testing, water-pump inspection and coolant replacement.

• Brakes and chassis: Hydraulic brake bleeding, master-cylinder service, caliper inspection, front-fork rebuilding, wheel checks and steering-head adjustment.

• Electrical diagnosis: System circuit diagrams, switch-continuity checks and troubleshooting charts for ignition, starting, charging, lighting and signaling faults.

Written primarily for Yamaha and MBK dealers and their qualified mechanics, this manual assumes basic mechanical knowledge and familiarity with scooter repair.

Engine Inspection and Overhaul

Step-by-step overhaul procedures extend to valve-guide replacement, valve-seat inspection and lapping, piston-ring clearance checks and cylinder measurement. Camshaft installation includes timing-mark references; crankshaft inspection covers runout, connecting-rod clearance and bearing condition.

The maintenance specifications let mechanics compare measured components with standard dimensions and wear limits when assessing reuse or replacement. Engine and chassis torque tables, cooling-system diagrams and lubrication diagrams provide the related service references.

Exploded assembly views are paired with job charts identifying parts, removal order, lubrication points and replacement items.

Sheaves, Clutch and Final Drive

Separate clutch-housing and spring specifications distinguish the two models. The transmission section also covers final-drive gears and shafts, rather than stopping at belt removal.

Drive-service cautions address grease contamination of the V-belt and clutch, which can lead to slipping and poor drive performance. The special-tool list identifies the clutch spring holder 90890-01337 and its holder arm 90890-01464.

Carburetor Checks and Cooling-System Service

Carburetor specifications distinguish the TEIKEI TK 5DS used on the XQ125 from the TK 5KD used on the XQ150. Fuel-level measurement, needle-valve inspection and autochoke tests support investigation of starting and running complaints.

The water-pump exploded view identifies the bleed screw and copper washer. The installation instructions specify replacement of the complete water-pump assembly. Radiator-fan and temperature-warning circuit checks complement the mechanical cooling-system procedures.

Brake, Fork and Steering Work

Brake coverage includes pad replacement, master-cylinder disassembly, caliper inspection and hydraulic bleeding. Front-fork procedures extend through internal inspection, seal installation, oil filling and oil-level measurement.

Fork-disassembly cautions identify potential damage to seals, bushings and the oil-flow stopper. The steering-head section warns that an incorrectly installed bearing race can damage the head pipe.

Safety notes address secure vehicle support during chassis work, brake-fluid handling and eye protection around battery electrolyte.

Electrical Fault Tracing

Ignition, electric-starting and charging circuit diagrams accompany component tests and diagnostic charts. Coverage includes starter-motor disassembly, brush and armature checks, fuel-sender testing and carburetor-heating diagnosis.

The complete XQ125/XQ150 wiring diagram includes wire-color codes and connector layouts. Together with the system-specific charts, it supports tracing faults through switches, wiring and components before replacement decisions are made.

Sample Valve, Thermostat and Charging Specifications

For both models, cold valve-clearance specifications are 0.10–0.14 mm intake and 0.16–0.20 mm exhaust. These values accompany the valve-adjustment procedures.

The thermostat specification lists a nominal opening temperature of 82°C. Electrical maintenance data lists normal charging-system output as 14 V, 170 W at 5,000 rpm, alongside coil-resistance specifications and charging-system tests.