| Feature | Specification |
|---|---|
| Production Years | 1977 – 1980 |
| Engine Type | 2-Stroke, Air-Cooled Single |
| Oil Capacity/Type | 0.6 L / SAE 10W-30 (Type SE) |
| Spark Plug | NGK B6HS (Gap: 0.6mm – 0.7mm) |
| Battery | 6N4-2A-4 (6V) |
| Tire Size (Front) | 2.50 – 18 4PR |
| Tire Size (Rear) | 3.00 – 16 4PR |
| Tire Pressure (F/R) | 1.2 bar / 1.5 bar |
The Yamaha TY 50 M (1G3) holds a unique place in motorcycling history as one of the few mopeds ever engineered with authentic competition trials geometry. Unlike many of its contemporaries that were merely ‘scrambler-styled’ street bikes, the TY 50 M was a direct descendant of the legendary TY series developed with the input of trials champion Sammy Miller. This pedigree allowed the 1G3 to offer genuine low-speed balance and technical capability in a package accessible to teenage riders.
Engineering Analysis
The 1G3 variant, produced between 1977 and 1980, features a robust 49cc two-stroke engine designed for torque rather than top-end speed. Its lightweight frame and high ground clearance mimic its larger siblings, the TY175 and TY250. The engineering focus was on reliability and manageable power delivery, making it an ideal entry point for off-road enthusiasts. The inclusion of a 5-speed gearbox allowed for precise control during technical maneuvers, a rarity in the 50cc class of the era.
Maintenance & Service Specifications
Maintaining the TY 50 M is straightforward, provided the technician adheres to the original Japanese engineering standards. At MotoSpecsLab, we emphasize the following critical service points:
Lubrication System
The transmission requires 0.6 Liters of SAE 10W-30 (Type SE) oil. Given the age of these machines, ensuring the oil is free of metal shavings is vital for preserving the clutch plates and gear teeth. Regular changes are recommended every 2,000 miles or annually.
Ignition & Electrical
The 1G3 utilizes an NGK B6HS spark plug. For optimal combustion and cold-start reliability, the gap must be set precisely between 0.6mm and 0.7mm. The electrical system is a 6V setup, powered by a 6N4-2A-4 battery. Modern owners should check for corrosion at the terminals, which is a common cause of dim lighting on vintage Yamahas.
Chassis & Tires
The trials-specific handling depends heavily on tire condition. The front 18-inch and rear 16-inch tires should be kept at 1.2 bar (17.4 psi) and 1.5 bar (21.7 psi) respectively for mixed-use riding. For dedicated off-road use, pressures can be adjusted slightly lower, though the 4PR (4-ply rating) tires provide significant sidewall stability.
MotoSpecsLab Verdict
The Yamaha TY 50 M – 1G3 is more than a vintage moped; it is a scaled-down piece of trials history. Its mechanical simplicity combined with purposeful design makes it a highly collectible and functional classic. Proper adherence to the 10W-30 oil specification and spark plug gapping ensures this 50cc engine remains as reliable today as it was in 1977.