Honda ST125 Dax (JB04 / JB06) — OEM Fluid, Tire Pressure & Maintenance Specs
124cc Air-Cooled Horizontal Single SOHC 2-Valve in Pressed T-Bone Frame (Wet Centrifugal 4-Speed) · Source: Honda ST125 Dax (JB04 / ST125A) Official Owner’s Manual Maintenance Specifications
According to the Honda ST125 Dax (JB04 / ST125A) Official Owner’s Manual Maintenance Specifications, the 2022–Present Honda ST125 Dax (JB04 / JB06) (chassis JB04/JB06/ST125A) requires 0.8 L (0.85 US qt) of SAE 10W-30 (JASO MA, API SJ or higher) engine oil for a drain-only change and 0.85 L (0.90 US qt) with filter service (15412-K0N-D01 / 15412-MGS-D21 (HF117)). Standard solo cold tire pressure is 200 kPa / 2.00 bar / 29 PSI front (120/70-12 M/C 51L) and 200 kPa / 2.00 bar / 29 PSI rear (130/70-12 M/C 56L), paired with 1× NGK CPR7EA-9S spark plug(s) and a YTZ5S battery.
Drain only: 0.8 L (0.85 US qt)
R 200 kPa (2.00 bar)
Est. Range: ~242 km (150 mi)
1. Engine Lubrication, Filter & Clutch Specifications
| Clutch Architecture | Wet Centrifugal Semi-Auto Clutch NEVER use JASO MB |
|---|---|
| Recommended Viscosity & Grade | SAE 10W-30 (Alt: SAE 10W-40) · JASO MA · API SJ or higher |
| Oil Volume (Drain / With Filter / Overhaul) |
• Drain only: 0.8 L (0.85 US qt) • With filter/strainer: 0.85 L (0.90 US qt) • Complete dry overhaul: 1 L (1.06 US qt) |
| OEM Oil Filter Code & Type | 15412-K0N-D01 / 15412-MGS-D21 (HF117) |
| Correct Oil Level Check Method | Hold upright on level ground; rest dipstick UNTHREADED on filler neck (do NOT screw in) |
| Oil Drain Bolt Torque | 24 N·m (17.7 lb-ft / 2.45 kgf·m) — Use fresh crush washer |
2. Cold Tire Pressures, Wheels, Ignition & Drivetrain
| Front / Rear OEM Tire Sizes | Front: 120/70-12 M/C 51L · Rear: 130/70-12 M/C 56L (Tubeless) |
|---|---|
| Cold Tire Pressure — Solo Riding |
Front: 200 kPa / 2.00 bar / 29 PSI Rear: 200 kPa / 2.00 bar / 29 PSI |
| Cold Tire Pressure — 2-Up / Loaded Touring |
Front: 200 kPa / 2.00 bar / 29 PSI Rear: 200 kPa / 2.00 bar / 29 PSI |
| OEM Spark Plug & Quantity | NGK CPR7EA-9S × 1 (Gap: 0.8–0.9 mm) |
| OEM Battery Code & Rating | YTZ5S (12V 3.5Ah MF AGM) |
| Final Drive Maintenance | 420 Sealed Chain (100 links, 15T/34T sprockets) — Maintain 25–35 mm slack |
| Brake Fluid & Coolant | DOT 4 · Air-Cooled Horizontal Engine (No liquid coolant) |
3. Ergonomics, Range & Scheduled Service Intervals
| Displacement · Max Power · Peak Torque | 124 cc · 9.4 hp @ 7,000 rpm · 10.8 N·m (8.0 lb-ft) @ 5,000 rpm |
|---|---|
| Seat Height & Wet Curb Weight | 775 mm (30.5 in) · 107 kg (236 lbs) |
| Fuel Tank & Est. Real-World Range | 3.8 L (1.0 US gal) · ~63.7 km/L → ~242 km (150 mi) |
| OEM Scheduled Maintenance Intervals |
• First Break-In: 1,000 km • Engine Oil / Filter: 6,000 km / 12,000 km • Air Filter / Spark Plug: 16,000 km / 12,000 km • Valve Clearance Check: 6,000 km |
4. Generation Cutoffs & Real-World Wrenching Gotchas
Model-Year & Chassis Generation Notes
Reviving the iconic pressed-steel T-bone frame in 2022 (JB04) and Euro 5+ 2025 (JB06), the ST125 Dax pairs the C125-derived 4-speed semi-automatic centrifugal clutch engine with a replaceable paper oil filter (15412-K0N-D01) and 2-up double seat.
Oil & Clutch Mechanical Engineering Note
Although clutch-leverless, the Dax 125 relies on a dual wet centrifugal and shift-drum multi-plate clutch running in crankcase oil—never pour JASO MB scooter oil! Use SAE 10W-30 JASO MA at 0.80 L drain-only or 0.85 L with paper filter replacement.
Garage Wrenching Gotchas
- Because the pressed T-bone chassis houses a compact 3.8 L under-seat fuel tank alongside the YTZ5S battery, flip up the double seat to refuel and plan stops around every 180–200 km.
- Unlike the Monkey’s 80-aspect block tires, the Dax wears street-focused 120/70-12 front and 130/70-12 rear tubeless tires rated at 200 kPa (29 PSI) cold solo or two-up.
5. Frequently Asked Questions (FAQ)
How does the Honda Dax 125 differ mechanically from the Monkey 125?
While the Monkey 125 uses a 5-speed hand-clutch gearbox (0.90 L oil with filter), the Dax 125 uses a 4-speed heel-and-toe centrifugal semi-auto transmission taking 0.80 L drain-only or 0.85 L with paper filter.
Can the Honda ST125 Dax legally carry a pillion passenger?
Yes—unlike the solo-only Monkey 125, the Dax 125 comes standard with a long two-person bench seat, passenger footpegs, and a chrome grab rail.
How do you properly check engine oil level on the Honda Dax 125?
Hold the bike vertically upright on flat ground, wipe the dipstick, rest it unthreaded on the filler neck without screwing it in, and verify oil sits within the crosshatched zone.