1987–2001 Yamaha SH50 Razz Service & Repair Manual (P/N LIT-11616-05-80)

• Coverage and document identity: Identifies the manual as SH50/M (T-A) and provides identification and specification data for SH50T (model code 2EK) and SH50MT (model code 2HU). Yamaha publication P/N LIT-11616-05-80, 1st edition, January 1990; 185-page PDF.
• Engine removal and overhaul: Details engine removal, complete disassembly, inspection, repair, and reassembly of the cylinder head, cylinder, piston and rings, crankshaft and crankcase, kick-start mechanism, centrifugal clutch and transmission, starter clutch and motor, CDI magneto, Autolube pump, drive axle, air shrouds, and exhaust parts.
• Carburetion and lubrication work: Covers carburetor removal, section-view identification, disassembly, float and jet inspection, assembly, installation, fuel-cock inspection, reed-valve service, idle and throttle-cable adjustment, compression testing, and Autolube pump air bleeding.
• Chassis repair procedures: Includes front and rear wheel removal, bearing and drum-brake inspection, wheel assembly, front-fork and steering-column disassembly, bearing-race service, steering adjustment, and rear shock absorber inspection.
• Electrical diagnosis: Provides the SH50T/SH50MT circuit diagram, component-location drawings, troubleshooting charts, and component checks for the electric starting, CDI ignition, charging, lighting, and signal systems, plus the full wiring diagram.
• Specifications, tools, and illustrations: Supplies component torque tables, capacities, wear limits, clearances, adjustment data, electrical test specifications, cable-routing drawings, exploded assembly views, and Yamaha special-tool references with part numbers.

Coverage and identification

Fitment is tied to the factory identifiers. The scooter-identification and specification sections list SH50T and SH50MT, with starting VINs JYA2EK00*HA000101 and JYA2HU00*HA000101 and engine numbers 2EK-000101 and 2HU-000101. Use these identifiers instead of relying only on a broad model-year range. The covered configuration is an air-cooled, single-cylinder two-stroke with separate Yamaha Autolube, electric and kick starting, a wet centrifugal automatic clutch, and a single-speed automatic transmission. The general specifications distinguish the SH50T at 6.9:1 compression from the SH50MT at 6.3:1.

Repair depth

The engine chapter is organized around actual bench work, not only routine service. Access procedures cover the tail cover and moles, footrest board, front panel and leg shield, and handlebar covers. The overhaul sequence then documents the cables, leads, hoses, carburetor, and exhaust removal needed to take the power unit out, followed by dedicated teardown, inspection, repair, and assembly subsections. Wear inspection covers cylinder-head warp, cylinder and piston condition, piston rings, crankshaft runout and connecting-rod play, clutch shoes and springs, kick-starter parts, and the Autolube pump. Reassembly pages combine labeled exploded views with lubrication symbols, fastener-specific torque callouts, oil-seal orientation, and final adjustment or operational checks.

Carburetor repair is treated as its own chapter rather than a basic cleaning note. The manual identifies the Y12P/Teikei Kikaki carburetor and covers internal inspection, float height, starter and pilot circuits, throttle valve and jet-needle setup, fuel-cock operation, and reed-valve condition. Periodic service sections add air-cleaner service, fuel-line inspection, transmission-oil replacement, brake and tire checks, steering adjustment, battery and fuse service, spark-plug inspection, headlight aim, and ignition-timing checks.

Diagrams, diagnostics, and tools

Electrical fault finding goes beyond a single schematic. Dedicated flowcharts trace no-crank, no-spark, no-charge, lighting, horn, turn-signal, brake-light, fuel-gauge, and oil-warning faults through switches, relays, coils, the starter motor, CDI magneto, regulator/rectifier, lamps, and wiring. Among the most useful drawings are the carburetor section view, crankcase/crankshaft and clutch/transmission exploded assemblies, front-fork/steering exploded view, system circuit diagrams, cable-routing views, and the full SH50T/SH50MT wiring diagram.

Factory tool callouts make it easier to plan specialized repair work before teardown. Engine sections reference the YU-01235 flywheel holding tool, YM-01189 magneto puller, YU-01135 crankcase separator, and YU-90050 crankshaft installation set; chassis and electrical work identify the YU-33975 ring-nut wrench, YU-03112 pocket tester, and YU-33260 electro tester.

The manual also identifies damage-prone assembly points. Forcing the crankcase halves or striking their gasket surfaces can ruin the sealing faces, while dragging the drive-axle threads or serrations across the oil-seal lip can create a leak. Support the scooter securely for engine, wheel, fork, and steering work, and follow the factory fuel, battery, and electrical safety warnings during diagnosis and repair.