2000–2004 Yamaha YQ100 / Aerox 100 Scooter Service Manual (P/N 5ME1-AE1)

This service manual covers the 2000–2004 Yamaha YQ100 / Aerox 100. Published by MBK Industrie as the 1st Edition in February 2000, it carries cover reference 5ME1-AE1.

• Engine repair: Engine removal, cylinder-head and piston inspection, crankcase separation, crankshaft checks, and reassembly procedures.

• Belt drive and clutch: Primary- and secondary-sheave disassembly, centrifugal-clutch inspection, kick-starter service, and transmission shaft and bearing checks.

• Fuel system: TEIKEI carburetor disassembly and inspection, reed-valve checks, vacuum-operated fuel-cock testing, and fuel-filter cleaning.

• Lubrication and maintenance: Autolube pump removal, installation and air bleeding, plus periodic maintenance tables, lubrication schedules, and idle and throttle-cable adjustments.

• Brakes and wheels: Front hydraulic-disc brake service, master-cylinder and caliper repair, rear drum-brake inspection, wheel-bearing replacement, and static balancing.

• Fork and steering: Telescopic front-fork disassembly, seal replacement, steering-head bearing service, and rear shock absorber inspection.

• Electrical diagnosis: Wiring diagrams, switch-continuity charts, ignition and starter tests, charging checks, and lighting and signal-system troubleshooting.

MBK Industrie wrote this manual primarily for Yamaha and MBK dealers and their qualified mechanics, assuming prior knowledge of scooter service and repair.

Engine, Autolube and Belt-Drive Repair

Top-end inspection covers cylinder-head warpage, cylinder bore and taper, piston-to-cylinder clearance, ring gaps, and piston-pin fit. Bottom-end coverage extends to crankcase sealing, crankshaft runout, connecting-rod play, and bearing inspection, with crankcase separating tool 90890-01135 identified.

Primary- and secondary-sheave sections distinguish roller, cam, collar, clutch-shoe, and housing checks. The clutch section specifies spring holder 90890-01337 and warns that uncontrolled release of the loaded secondary-sheave assembly can cause injury.

Autolube coverage includes the pump drive gear, oil hoses, and the requirement for air bleeding after pump installation. Exploded diagrams and job instruction charts accompany the assembly sections, supported by component-specific tightening torques and lubrication data.

Carburetor Inspection and Fuel Delivery

Carburetor inspection addresses blocked jets and passages, needle-valve wear, throttle-valve movement, and the starter plunger. The float height is factory-set; the TEIKEI chapter explicitly cautions against adjusting it.

Fuel-cock tests distinguish vacuum-operated fuel flow from leakage. The reed-valve section adds sealing checks, stopper-height measurements, and clearance criteria.

Hydraulic Brakes, Wheels and Suspension

Front-brake procedures extend to master-cylinder and caliper disassembly, internal inspection, reassembly, and hydraulic bleeding. Rear-brake coverage deals with shoes, drum condition, the brake camshaft, and wear-indicator alignment.

Wheel sections include brake-disc runout and thickness checks, speedometer-drive inspection, and wheel balancing. Fork procedures cover damper rods, springs, seals, and oil filling; the disassembly warning explains how bottoming the inner tube can damage the oil-flow stopper.

Review the factory safety notices before servicing the hydraulic brake system or spring-loaded clutch assembly.

Circuit Diagrams and Fault Isolation

Separate Ignition and Starting System, Charging System, Lighting System, and Signal System circuit diagrams accompany the diagnostic charts. Wire-color legends and switch-continuity tables support tracing faults through the harness.

The no-spark charts distinguish pickup-coil, source-coil, ignition-coil, plug-cap, wiring, and CDI faults, helping narrow down the cause before replacing the CDI unit. Starter-motor inspection adds armature-insulation, commutator, and brush checks; fuel-sender testing covers full and empty tank conditions.

Cable-routing drawings show harness, hose, and control-cable arrangements. A metric-to-imperial conversion table supports the manual's metric specifications.

A Preview of Cylinder, Oil and Ignition Data

The following figures are a small sample of the inspection and service specifications in this manual.

For the YQ100 top end, the cylinder inspection section lists a bore wear limit of 52.10 mm and standard piston-to-cylinder clearance of 0.044–0.045 mm.

Transmission lubrication data distinguish a 0.11 L periodic oil change from the 0.13 L total capacity for SAE 85W/140 type SE oil. The CDI pickup-coil test specifies 400–600 ohms at 20°C.

Searchable PDF with Chapter Bookmarks

Search and diagram detail: Embedded text supports keyword searches, and nine PDF bookmarks link to the chapters and final wiring diagram. Small wiring labels are best read with zoom.

File contents: One printable English PDF with 232 pages. The total includes six opening pages, eight chapter dividers, ten chapter contents pages, and the final landscape wiring diagram.