HT1B
Category: Enduros
Manufacturer: Yamaha
Hits: 716
| Year | 1971 |
| Engine Class | 90 |
| VIN Prefix | HT1 |
| Known VIN Range (Vehicle ID Numbers) | 215101 to 229459 |
| Tank Color(s) | Metallic Purple |
| Country of Sale | USA |
| Bore (MM) | 50 |
| Stroke (MM) | 45.6 |
| Displacement (CC) | 89 |
| Compression Ratio (to 1) | 6.8 |
| BHP @ RPM | 8.5 @ 8,000 |
| Autolube Injection? | Yes |
| Engine Cooling | Air |
| Carburetor Model | VM20SC |
| Ignition Type | Magneto |
| Ignition Timing MM (BTDC) | 1.8 |
| Primary Drive Gearing | 3.9 |
| Final Drive Gearing (Sprockets) | 49/14 |
| Box Gearing First | 3.18 |
| Box Gearing Second | 2.0 |
| Box Gearing Third | 1.37 |
| Box Gearing Fourth | 1.0 |
| Box Gearing Fifth | 0.8 |
| Fuel Capacity (L) | 6.5 |
| 2 Stroke Oil Tank Capacity (L) | 1.2 |
| Gearbox Oil Capacity | 0.75 |
| Fork Oil Capacity (CC/Fork Leg) | 140 |
| Front Tire (stock) | 2.75 x 18 |
| Rear Tire (stock) | 3.00 x 18 |
| Front Brake Type | Drum |
| Rear Brake Type | Drum |
| Rear Suspension | Twin Shock |
| Overall Width (mm) | 900 |
| Ground Clearance (mm) | 225 |
| Wheelbase (mm) | 1,220 |
| Dry Weight (kg) | 85 |
| Voltage | 6 Volt |
| Carburetor Type | VM20SC |
| Main Jet | 85 |
| Needle Jet | N-6 |
| Jet Needle | 4D3-3 |
| Slide Cutaway | 2.0 |
| Pilot Jet | 30 |
| Air Screw (turns out) | 1.75 |
| Starter Jet | 40 |
| Float Level (mm) | 22.5 |