Yamaha TT225/TT225S Service Manual, 1986–1987 (P/N LIT-11616-05-18)

Yamaha factory service manual for the TT225S, model code 1RH, first edition, November 1985. Manufacturer references: P/N LIT-11616-05-18 and 1RH-28197-10.

PDF Bookmarks, Text Search and Diagram Detail

Search and navigation: PDF text search is unavailable. Embedded bookmarks cover chapters and many subsections. Small labels in the full wiring diagram are readable when enlarged; gray-shaded areas in the ignition and lighting circuit diagrams have lower contrast.

ZIP download containing one printable 199-page PDF in English, including five opening pages, three otherwise blank pages, and the final unnumbered wiring diagram. The opening pages contain the cover, copyright information, reading guide, symbols and chapter index.

Engine Overhaul, Chassis Service and Electrical Diagnosis

The following coverage highlights are a selection from the manual; additional topics include fuel-cock service and air-filter maintenance.

• Engine overhaul: Removal, teardown, inspection, repair and reassembly of the cylinder head, camshaft, rocker arms, piston/cylinder, crankshaft and connecting rod.

• Drivetrain and lubrication: Clutch and primary-drive repair, oil-pump service, balancer assembly, kickstarter repair, and constant-mesh six-speed transmission/shifter disassembly and reassembly.

• Periodic adjustments: Valve-clearance and decompression-cable adjustment, ignition-timing and compression checks, oil/filter service with oil-flow verification, clutch adjustment, and drive-chain maintenance.

• Carburetion: Y26P/TK-KIKAKI carburetor disassembly, inspection and assembly, with a section view, fuel-level adjustment and full-throttle adjustment.

• Brakes and chassis: Front disc-brake overhaul and bleeding, rear drum-brake inspection, wheel-bearing replacement, front-fork rebuilding, steering-head service and Monocross suspension/linkage checks.

• Electrical troubleshooting: Ignition and lighting fault-finding charts, CDI magneto and pickup/source-coil checks, switch-continuity tests, circuit diagrams and the complete wiring diagram.

• Factory references: Engine, chassis and electrical specification tables, component torque data, lubrication diagrams, cable-routing drawings and special-tool references.

Written primarily for Yamaha dealers and qualified mechanics, this manual assumes a working knowledge of motorcycle repair concepts and procedures.

Engine Inspection and Assembly Details

The engine sections address the 223 cc, four-stroke SOHC four-valve single, with wet-sump lubrication and kick starting. Step-by-step procedures extend to valve-guide replacement, valve-seat cutting and lapping, cam-chain and decompression-cam service, crankcase work, bearings and oil seals.

Yamaha identifies piston, clutch, carburetor and AC-magneto work that can be performed without removing the engine. Dedicated assembly instructions cover component positioning, crankcase closure, CDI rotor installation, cylinder-head timing and final adjustments; exploded views clarify component order.

During cam-timing work, incorrect camshaft rotation can damage the piston and valves. The bearing instructions also warn that spinning dry bearings with compressed air can damage their running surfaces.

Carburetor Circuits and Chassis Repair Limits

The carburetor section view distinguishes the coasting-enricher, main/slow, fuel and starter circuits. Inspection procedures address the rubber diaphragm, starter plunger, float needle and seat, piston valve, jet needle and jets.

Brake and suspension work: Front-brake instructions extend through caliper and master-cylinder disassembly, inspection and assembly. Rear-brake coverage includes shoe, drum and camshaft checks; swingarm service includes side-play measurement, shim selection, and relay-arm/connecting-rod inspection.

Rear-shock coverage includes preload and damping adjustment, handling, removal, inspection and installation, without an internal shock-rebuilding procedure. Fork-oil changes, steering-head adjustment, wheel-bearing checks and headlight service are also documented.

Follow the manual's fluid, support and pressure-handling precautions for brake and suspension work.

Ignition Fault Tracing and Lighting Tests

The TT225S circuit diagram and separate ignition-system and lighting-system circuit diagrams support the troubleshooting charts. For a no-spark or weak-spark fault, the charts connect plug, cap, coil, switch, wiring and CDI checks into a diagnostic path, helping distinguish a connection fault from a failed component.

Whole-system ignition checks and ignition-coil spark-gap tests use the YU-33260 Electro Tester. Lighting diagnosis includes generator-output checks, lighting-coil resistance testing and rectifier/regulator checks.

Special Tools and Workshop Tables

Tool references include the YM-91042 clutch holder and YM-01080 rotor puller. The YM-08035 valve-adjusting tool and YM-01300-1 front-fork cylinder holder are identified for their respective service operations.

The appendix brings together clearances, wear limits, capacities, gearing, carburetor settings, suspension/brake data and electrical test specifications. A general torque chart and unit definitions supplement the component-specific tightening data.

A Preview of Clutch Limits and Ignition-Coil Values

For clutch inspection, standard friction-plate thickness is 2.9–3.1 mm, with a 2.8 mm wear limit. These are separate from the clutch-plate warpage checks covered in the same repair section.

The C2T4/Yamaha ignition coil has a specified primary resistance of 1.6 Ω ±10% and secondary resistance of 6.6 kΩ ±20%, both at 20°C (68°F). The electrical chapter pairs resistance measurements with fault-finding charts and spark-gap testing.