1978 Yamaha YZ100 Specifications and Specs
Specifications, manuals and workshop reference information.
Note: Specs are compiled from factory data, manuals and owner feedback. Bikes vary — if yours is different, jump into the forum and share it.
General Specifications
| Engine Type | Air-cooled, two-stroke, torque induction |
| Displacement | 123 cc |
| Bore × Stroke | 56 × 50 mm |
| Compression Ratio | 7.4 : 1 |
| Maximum Power | Not specified |
| Maximum Torque | Not specified |
| Carburetor | Mikuni VM32SS | Replacement Options |
| Lubrication | Premix |
| Fuel Mix Ratio | 20 : 1 | Premix Calculator |
| Ignition | CDI magneto |
| Spark Plug | N-59G / Champion |
| Spark Plug Gap | 0.7 mm |
Transmission
| Transmission Type | Constant mesh, 6-speed |
| Clutch | Wet multi-plate |
| Primary Reduction | 71 / 22 (3.227) |
| Final Reduction | 51 / 12 (4.250) |
| Overall Reduction | Not specified |
Dimensions
| Overall Length | 2100 mm |
| Overall Width | 900 mm |
| Overall Height | 1180 mm |
| Wheelbase | 1420 mm |
| Ground Clearance | 295 mm |
| Fuel Tank Capacity | 5.8 L |
| Bearing Sizes |
Bearing Finder |
Chassis
| Frame Type | Chrome-molybdenum steel tubular, semi double cradle |
| Caster Angle | 30° |
| Trail | 133 mm |
| Front Suspension | Telescopic fork | Fork Oil Levels |
| Rear Suspension | Monocross |
| Front Suspension Travel | 230 mm |
| Rear Suspension Travel | 240 mm |
Brakes & Wheels
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