Honda Monkey 125 (JB03 / JB05 5-Speed) — OEM Fluid, Tire Pressure & Maintenance Specs
124cc Air-Cooled Horizontal Single SOHC 2-Valve Long-Stroke (5-Speed Wet Multi-Plate) · Source: Honda Monkey 125 (JB03 / Z125MA) Official Owner’s Manual Maintenance Specifications
According to the Honda Monkey 125 (JB03 / Z125MA) Official Owner’s Manual Maintenance Specifications, the 2022–Present Honda Monkey 125 (JB03 / JB05 5-Speed) (chassis JB03/JB05/Z125MA) requires 0.85 L (0.90 US qt) of SAE 10W-30 (JASO MA, API SJ or higher) engine oil for a drain-only change and 0.9 L (0.95 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 (120/80-12 65J) and 200 kPa / 2.00 bar / 29 PSI rear (130/80-12 69J), paired with 1× NGK CPR7EA-9S spark plug(s) and a YTZ5S battery.
Drain only: 0.85 L (0.90 US qt)
R 200 kPa (2.00 bar)
Est. Range: ~375 km (233 mi)
1. Engine Lubrication, Filter & Clutch Specifications
| Clutch Architecture | Wet Multi-Plate Manual 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: 0.85 L (0.90 US qt) • With filter/strainer: 0.9 L (0.95 US qt) • Complete dry overhaul: 1.1 L (1.16 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: 120/80-12 65J · Rear: 130/80-12 69J (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 Drive Chain (98 links, 14T/37T sprockets) — Maintain 20–30 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 @ 6,750 rpm · 11 N·m (8.1 lb-ft) @ 5,500 rpm |
|---|---|
| Seat Height & Wet Curb Weight | 775 mm (30.5 in) · 104 kg (229 lbs) |
| Fuel Tank & Est. Real-World Range | 5.6 L (1.5 US gal) · ~67 km/L → ~375 km (233 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
From 2022 onward (JB03 and 2025+ JB05 5-speed models), the Monkey 125 switched to the long-stroke 50.0 mm bore engine with an external paper oil filter element (15412-K0N-D01 / 15412-MGS-D21). Earlier 2018–2021 4-speed JB02 engines lacked a paper cartridge filter.
Oil & Clutch Mechanical Engineering Note
Equipped with a cable-operated wet multi-plate manual clutch, the Monkey 125 requires SAE 10W-30 JASO MA oil. Refill volume is ~0.85 L drain-only and 0.90 L when opening the 2-bolt right cover to swap the paper filter cartridge—do not dump in a full 1.0 L bottle.
Garage Wrenching Gotchas
- Insert the coil spring into the crankcase cavity first and face the rubber seal side (marked OUT-SIDE) of the 15412-K0N-D01 paper element toward the outer cap to prevent oil starvation.
- As a factory solo-seat machine running high-profile 80-series 12-inch tubeless tires, cold inflation pressure is 200 kPa (29 PSI) front and 200 kPa (29 PSI) rear.
5. Frequently Asked Questions (FAQ)
What oil volume and oil filter part number fit the 5-speed Honda Monkey 125?
The 5-speed JB03/JB05 Monkey 125 takes 0.90 L (0.95 US qt) of SAE 10W-30 JASO MA oil with paper filter element 15412-K0N-D01 / 15412-MGS-D21 (or ~0.85 L without opening the filter cap).
Does the Honda Monkey 125 run tubeless tires?
Yes—its 12-inch cast-alloy wheels mount 120/80-12 front and 130/80-12 rear tubeless tires inflated to 200 kPa (29 PSI) cold.
Why does the Monkey 125 seat feel plush and wide despite being a mini-moto?
Its thickly padded tuck-and-roll saddle has a wide profile, yet plush rear shocks compress noticeably under rider weight and the featherweight 104 kg curb mass makes balancing effortless.