Yamaha Jog 50 CE50/CG50 Service Manual Set, 1986–1991 (P/N LIT-11616-05-43)

The CE50T supplement updates the base service information, while the CG50U supplement requires both earlier publications. With all three included, a CG50U owner has the base repair procedures and later model-specific changes in one reference.

Text Search, Chapter Bookmarks, and Wiring Detail

Search and diagram access: Embedded OCR supports text searches across the service chapters, although recognition is incomplete in wiring diagrams. Chapter bookmarks cover all three publications; the external main-index link requires a separate file that is not included. Small labels in the three full wiring diagrams are legible when enlarged.

One printable, English-language PDF is supplied in a ZIP download. The 282-page PDF includes the publications listed above plus two opening pages: the combined CE50 (S-T) cover, P/N LIT-11616-CE-50, and its blank reverse. Original covers and blank pages within the publications are already included in their page counts.

Two-Stroke Overhaul, Autolube Service, and Electrical Diagnosis

The selected coverage below highlights major service areas; additional topics include fuel-cock cleaning and headlight-beam adjustment.

• Engine overhaul: Step-by-step engine removal, crankcase separation, crankshaft installation, cylinder and piston inspection, piston-ring checks, and engine reassembly.

• Drive and starting mechanisms: Primary and secondary sheave service, dry centrifugal automatic clutch disassembly, V-belt inspection, transmission repair, and electric/kick starter mechanisms.

• Autolube service: Pump cable adjustment, pump and drive-gear inspection, delivery-system air bleeding, and model-specific engine-oil level checks.

• Carburetion: Carburetor disassembly and reassembly, electric auto-choke testing, float inspection, and reed-valve removal, inspection, and installation.

• Brakes and chassis: Wheel removal, brake-shoe plate service, drum and lining inspection, steering-bearing adjustment, front-fork overhaul, and rear shock absorber inspection.

• Electrical diagnosis: Troubleshooting charts and component checks for starting, ignition, charging, lighting, signals, and auto-choke circuits, with model-specific wiring diagrams and cable-routing drawings.

Written primarily for Yamaha dealers and qualified mechanics, these publications assume familiarity with scooter repair concepts and procedures.

Engine Inspection and Drive-System Repair

The base manual covers the 49 cm³ single-cylinder engine beyond routine maintenance. Internal repair information includes piston-pin and bearing inspection, C.D.I. magneto removal and installation, transmission gears and bearings, and complete engine assembly.

Secondary-sheave procedures address torque-cam grooves, guide pins, seals, and clutch components. Starter coverage extends to the starter clutch, wheel gear, idler gear, and kick-start mechanism.

Yamaha’s cautions identify compressed-air spinning of dry bearings as a cause of bearing-surface damage and warn that forced crankcase separation or blows to gasket mating surfaces can damage the cases.

CE50T Steering and CG50U Changes

The CE50T supplement concentrates on revised handlebar-cover work, steering adjustment, front-fork service, bearing-race replacement, specifications, cable routing, and its wiring diagram. Its steering instructions explain how uneven bearing-race installation can damage the frame or steering column.

CG50U body procedures cover tail covers and moles, the front panel, leg shield, footrest board, and handlebar covers. Revised Autolube bleeding and oil-level checks accompany electrical changes for the added fuel meter and fuel sender and the changed oil-level gauge.

CE50S and CE50T specifications list a 2.9 L fuel tank and 2.75-10 tires; CG50U specifications list a 3.5 L tank and 3.00-10 tires. CG50U secondary reduction is 38/10 (3.800), compared with 36/12 (3.000) for CE50S and CE50T.

Clutch-in speed is 2,300–2,700 r/min for CE50S/CE50T and 3,150–3,650 r/min for CG50U. Their respective clutch-stall ranges are 3,700–4,300 and 4,650–5,350 r/min.

Carburetor and Lubrication Differences

The Y12P/TEIKEI KIKAKI carburetor chapter explains the electric auto-choke’s P.T.C. thermistor, wax element, and starter plunger. Temperature-dependent plunger checks complement the electrical auto-choke tests and reed-valve inspection procedures.

CG50U specifications identify carburetor 2YR00 with a #90 main jet, an Autolube pump stroke of 0.34–0.55 mm, and a spark-plug gap of 0.6–0.7 mm. The transmission specifications distinguish periodic-change filling from the 0.11 L total oil volume.

Circuit Drawings and Factory Tools

The Auto Choke System wiring schematic and Carburetor section view explain enrichment and metering operation. The Electrical Starting System circuit diagram and Ignition System circuit diagram connect the troubleshooting charts to component checks. Separate CE50S, CE50T, and CG50U wiring diagrams document their harness connections.

Engine-tool references include Compression Gauge YU-33223, Flywheel Magneto Puller YM-01189, Clutch Spring Holder YS-28891, Crankcase Separating Tool YU-01135, and Crankshaft Installation Set YU-90050. Electrical checks reference Pocket Tester YU-03112.

Examples of Compression, Wear, and Float-Inspection Data

CE50S compression-testing data specify 784 kPa (114 psi) as standard and 628 kPa (91 psi) as the minimum at sea level, with a warmed engine cranked at fully open throttle.

Across the three publications, engine inspection tables list a 40.1 mm cylinder-bore wear limit and 0.034–0.047 mm piston clearance. Cylinder-head fastener torque is 10 Nm (7.2 ft-lb).

Drive-system specifications give a 15.0 mm V-belt width with a 13.5 mm wear limit. Clutch-shoe thickness is 4.0 mm, with a 2.5 mm wear limit.

The CE50S carburetor inspection specifies a 16.0 ± 1.0 mm float height, measured with the float-chamber gasket removed and the needle valve uncompressed. The float height is factory-set.

Technical data here is a preview; consult the complete OEM procedures before work on the brakes, fuel system, or spring-loaded clutch.