Yamaha CW50 Workshop Manual Set, 1998–2000 (P/N 4VV-AE1)

The 1998 workshop manual covers routine maintenance, engine and drive overhaul, and chassis repair. The 2000 supplement updates electrical troubleshooting and provides a separate wiring diagram for that model.

For complete service information on the 2000 CW50, the supplement specifies a separate companion publication, the 1999 CW50 Service Manual (4VV-ME1).

Searchable Text and Wiring Sheets

Search and navigation: The PDF has searchable text and bookmarks for the workshop chapters, the supplement and its contents, and both full-system wiring sheets. Zoom in to read the smallest wire codes and connector labels.

One printable PDF contains 219 pages, including both covers, eight chapter dividers, and two large-format wiring sheets.

Workshop Repairs and Electrical Diagnosis

This selection of workshop topics draws from both publications. Other covered tasks include headlight aiming and body panel removal.

• Engine overhaul: Engine removal, crankcase separation, crankshaft installation, and cylinder, piston, and ring inspection.
• V-belt drive and starting mechanisms: Primary and secondary pulley service, dry centrifugal clutch inspection, reduction gear repair, and kick-starter service.
• Carburetors and fuel delivery: Separate DELL'ORTO and TEIKEI disassembly and reassembly procedures, fuel valve testing, and reed valve inspection.
• Routine maintenance: Idle speed and throttle cable adjustment, spark plug checks, transmission oil changes, and service intervals.
• Front disc and rear drum brakes: Caliper and master cylinder repair, hydraulic bleeding, and rear brake shoe replacement.
• Fork and steering: Front fork teardown, seal replacement, and steering head bearing inspection and adjustment.
• Electrical troubleshooting: No-spark, no-crank, charging, lighting, and signal faults, with switch continuity charts and circuit diagrams.

MBK INDUSTRIE wrote both publications for Yamaha and MBK dealers and qualified mechanics familiar with scooter repair.

Autolube, Carburetors, and Internal Drive

Autolube: The workshop manual covers oil pump removal and installation, feed hose and drive gear inspection, and bleeding the oil system.

Carburetor inspection: Separate tables give jetting, jet needle, and pilot air screw settings for the DELL'ORTO PHBN 12 HS and TEIKEI 5FX. The inspection procedures cover throttle slide movement, choke components, float needles, seats, and fuel passages. Float height is factory-set, and the manual warns that uneven tightening can distort the reed valves and carburetor coupling.

Internal drive work: The transmission procedures reach the shafts, bearings, and seals inside the reduction gearbox. Special-tool references include the crankcase separator (90890-01135), rotor extractor (90890-01189), and clutch spring retaining tool (90890-01337).

The symptom-based troubleshooting chapter helps narrow down hard starting, poor idle, weak acceleration, overheating, and unstable steering before parts are removed.

Wheel, Brake, and Chassis Service

Wheel service includes axle and rim runout checks, bearing inspection, and speedometer drive checks. Rear brake coverage shows how the cam and wear indicator align. The rear shock section covers removal, inspection, and replacement.

The steering section warns that incorrectly installed bearing races can damage the frame. The cable routing drawings show harness clamps, front brake hose guides, and throttle and choke cable paths, including points where the harness can be pinched during reassembly.

Exploded views of the crankshaft and crankcases and of the brake caliper and disc show how components, seals, and fasteners fit together.

Ignition, Starter, and Charging Tests

The ignition and starting diagrams show the CDI, starter relay, switches, and their connections. No-spark charts help distinguish an ignition component fault from a wiring or connection problem. Starter inspection covers the armature, commutator, brushes, and bearings.

Electrical reference data includes pickup and ignition coil resistance, charging system checks, and starter wear limits. Internal engine work and high-tension ignition testing require precise measurements and specialized tools. Consult a qualified Yamaha technician if you are unfamiliar with these procedures.

Sample Overhaul Limits and Ignition Test Values

For the 1998 CW50, the workshop manual gives a cylinder head distortion limit of 0.02 mm and a crankshaft runout limit of 0.03 mm. The V-belt wear limit is 15.7 mm in width. The specifications chapter also lists tightening torques, lubricant and fluid capacities, and piston and ring clearances.

Both publications give a CDI source coil resistance range of 640–960 Ω at 20°C (68°F) for no-spark diagnosis.