Yamaha Vox XF50 (SA31J 4T FI) — OEM Fluid, Tire Pressure & Maintenance Specs
49cc Liquid-Cooled Single SOHC 3-Valve FI (34L Box-Trunk Utility) · Source: Yamaha Vox XF50 (SA31J 4T FI) (2006–2016) Official Owner’s Manual Maintenance Specifications
According to the Yamaha Vox XF50 (SA31J 4T FI) (2006–2016) Official Owner’s Manual Maintenance Specifications, the 2006–2016 Yamaha Vox XF50 (SA31J 4T FI) (chassis SA31J/SA52J/3B3) requires 0.78 L (0.82 US qt) of SAE 10W-40 (JASO MB, API SG or higher) engine oil for a drain-only change and 0.78 L (0.82 US qt) with filter service (B65-E3411-00 (Oil Strainer Screen)). Standard solo cold tire pressure is 150 kPa / 1.50 bar / 22 PSI front (120/90-10 57J) and 150 kPa / 1.50 bar / 22 PSI rear (120/90-10 57J), paired with 1× NGK CR7E spark plug(s) and a YTX5L-BS battery.
Drain only: 0.78 L (0.82 US qt)
R 150 kPa (1.50 bar)
Est. Range: ~216 km (134 mi)
1. Engine Lubrication, Filter & Clutch Specifications
| Clutch Architecture | Dry Centrifugal CVT Belt Drive |
|---|---|
| Recommended Viscosity & Grade | SAE 10W-40 (Alt: SAE 10W-30) · JASO MB · API SG or higher |
| Oil Volume (Drain / With Filter / Overhaul) |
• Drain only: 0.78 L (0.82 US qt) • With filter/strainer: 0.78 L (0.82 US qt) • Complete dry overhaul: 0.85 L (0.90 US qt) |
| OEM Oil Filter Code & Type | B65-E3411-00 (Oil Strainer Screen) |
| Correct Oil Level Check Method | Hold upright on level ground; rest dipstick UNTHREADED on filler neck (do NOT screw in) |
| Oil Drain Bolt Torque | 20 N·m (14.8 lb-ft / 2.04 kgf·m) — Use fresh crush washer |
| Final Drive / Bevel Gear Oil | 100 ml (0.10 L) — SAE 10W-30 / 10W-40 (100 ml rear gear oil) |
2. Cold Tire Pressures, Wheels, Ignition & Drivetrain
| Front / Rear OEM Tire Sizes | Front: 120/90-10 57J · Rear: 120/90-10 57J (Tubeless) |
|---|---|
| Cold Tire Pressure — Solo Riding |
Front: 150 kPa / 1.50 bar / 22 PSI Rear: 150 kPa / 1.50 bar / 22 PSI |
| Cold Tire Pressure — 2-Up / Loaded Touring |
Front: 150 kPa / 1.50 bar / 22 PSI Rear: 175 kPa / 1.75 bar / 25 PSI |
| OEM Spark Plug & Quantity | NGK CR7E × 1 (Gap: 0.8–0.9 mm) |
| OEM Battery Code & Rating | YTX5L-BS (12V 4.0Ah MF AGM) |
| Final Drive Maintenance | Dry V-Belt CVT Drive — Inspect/replace V-belt and rollers every 20,000–24,000 km |
| Brake Fluid & Coolant | DOT 4 · Silicate-free ethylene-glycol OAT coolant for aluminum radiators (50:50 premix) |
3. Ergonomics, Range & Scheduled Service Intervals
| Displacement · Max Power · Peak Torque | 49 cc · 4.2 hp @ 8,000 rpm · 4.1 N·m (3.0 lb-ft) @ 6,500 rpm |
|---|---|
| Seat Height & Wet Curb Weight | 735 mm (28.9 in) · 89 kg (196 lbs) |
| Fuel Tank & Est. Real-World Range | 4.5 L (1.2 US gal) · ~48 km/L → ~216 km (134 mi) |
| OEM Scheduled Maintenance Intervals |
• First Break-In: 1,000 km • Engine Oil / Filter: 4,000 km / 8,000 km • Air Filter / Spark Plug: 12,000 km / 8,000 km • Valve Clearance Check: 12,000 km |
4. Generation Cutoffs & Real-World Wrenching Gotchas
Model-Year & Chassis Generation Notes
Sold as the Vox in Japan and C3 in North America (SA31J/SA52J), it paired Yamaha’s 49cc liquid-cooled 3-valve FI engine with a side-hinged 34 L cargo box and fat 120/90-10 tires.
Oil & Clutch Mechanical Engineering Note
Pushing 89 kg and wide 120/90-10 balloon tires with 49cc, change its 0.78 L of SAE 10W-40 JASO MB oil every 1,500–2,000 km and watch for milky water-pump seal wear.