The Grom (MSX125) is Honda's 125 cc mini bike that created the modern miniMOTO segment in 2014. The first 2014-2016 generation had a carbureted-look SOHC engine and four-speed gearbox; the 2017-2020 refresh documented by the 2018 US owner's manual brought a five-speed gearbox and refreshed styling, with a further update in 2021. Servicing is as simple as it gets: just 0.9 L of 10W-30 oil with no filter to change, an 8-inch-wheeled 420 chain with 106 links and 30-40 mm slack, equal 29 psi tire pressures and a tiny YTZ5S battery. Honda allows DOT 3 or DOT 4 brake fluid. Plug choice depends on usage - CPR6EA-9 standard, one grade hotter for sustained high-speed riding.
| Specification | Value | Source |
|---|---|---|
| Engine oil & filter | per Maintenance Schedule | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Specification | Value | Source |
|---|---|---|
| Oil capacity (without filter) | 0.9 Lafter draining (1.0 US qt); no oil filter element | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Oil type | Pro Honda GN4 4-stroke oil (USA & Canada) or Honda 4-stroke oil | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Oil viscosity | SAE 10W-30API SG or higher, JASO MA | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Brake fluid type (DOT) | DOT 3 or DOT 4Honda DOT 4 Brake Fluid or equivalent | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Fuel capacity | 5.7 L1.51 US gal | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Specification | Value | Source |
|---|---|---|
| Battery | YTZ5S, 12V 3.5 Ah | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Headlight bulb | LED | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Spark plug | NGK CPR6EA-9 or DENSO U20EPR9for extended high-speed riding: CPR7EA-9 / U22EPR9 | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Spark plug gap | 0.80-0.90 mm | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Specification | Value | Source |
|---|---|---|
| Front tire size | 120/70-12 51L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Rear tire size | 130/70-12 56L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Front tire pressure (solo) | 29 psi200 kPa | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Rear tire pressure (solo) | 29 psi200 kPa | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
| Chain size | DID 420, 106 links | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) |
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| Value | Source | Checked |
|---|---|---|
| Oil capacity (without filter): 0.9 L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Oil type: Pro Honda GN4 4-stroke oil (USA & Canada) or Honda 4-stroke oil | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Oil viscosity: SAE 10W-30 | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Brake fluid type (DOT): DOT 3 or DOT 4 | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Fuel capacity: 5.7 L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Engine oil & filter: per Maintenance Schedule | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Battery: YTZ5S, 12V 3.5 Ah | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Headlight bulb: LED | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Spark plug: NGK CPR6EA-9 or DENSO U20EPR9 | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Spark plug gap: 0.80-0.90 mm | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Front tire size: 120/70-12 51L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Rear tire size: 130/70-12 56L | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Front tire pressure (solo): 29 psi | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Rear tire pressure (solo): 29 psi | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Chain size: DID 420, 106 links | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |
| Chain Slack: 30-40 mm | 2018 Honda Grom MSX125 Owner's Manual (Honda MotoPub, US) (p. Specifications, Service Data) | 2026-11-03 |