This page covers Honda's Z125 Pro and Monkey 125, two miniMOTO models sharing a 124.9cc air-cooled single-cylinder engine family. The Z125 Pro (2017-2022 US) is a pit-bike-styled mini with a four-speed transmission, while the Monkey 125 (2019+ US) is a retro tribute to Honda's original 1960s Monkey bike with a five-speed gearbox. Both use fuel injection, 12-inch wheels, and disc brakes front and rear. These are among the most heavily customized Hondas on the market, so used OEM parts see strong demand for both restoration and project builds. Z125 and Monkey parts at Sun Coast Cycle Sports are individually inspected and cataloged at our Florida facility.
Z125 Pro and Monkey 125 generation and parts compatibility
| Model | US years | Engine | Key details |
|---|
| Z125 Pro | 2017-2022 | 124.9cc air-cooled single, 4-speed | Pit-bike styling, low seat, single disc front/rear. Discontinued after 2022. |
| Monkey 125 (Gen 1) | 2019-2021 | 124.9cc air-cooled single, 4-speed | Retro styling, chrome fenders, single disc front. No ABS. |
| Monkey 125 (Gen 2) | 2022+ | 124.9cc air-cooled single, 5-speed | Five-speed transmission, ABS standard, revised styling, updated LCD dash. |
The Z125 Pro and Monkey 125 share their basic engine architecture with the Honda Grom (MSX125). Internal engine components (piston, valves, crankshaft, oil pump) interchange between all three models within the same transmission configuration. The Z125 Pro and 2019-2021 Monkey both use four-speed transmissions, while the 2022+ Monkey uses a five-speed (matching the 2022+ Grom). Four-speed and five-speed transmission internals do not cross. Each model uses a different frame, bodywork, exhaust, and wheel configuration, so chassis and body parts are model-specific and do not interchange between Z125, Monkey, and Grom.
Within the Z125 Pro lineup (2017-2022), all parts interchange across model years. Within the Monkey 125, the 2022 update brought the five-speed gearbox, ABS, and minor bodywork changes that create a compatibility split. The 2019-2021 and 2022+ Monkey share the same frame and most bodywork, but the engine cases differ due to the transmission change, and brake hardware differs between ABS and non-ABS versions.
Common Z125 Pro and Monkey 125 failure points and replacement parts
Neither the Z125 Pro nor the Monkey 125 has any NHTSA recalls or documented systemic mechanical failures. The 125cc air-cooled single is one of Honda's simplest and most reliable engine designs. Most parts purchases are driven by crash damage, customization projects, or standard wear.
Crash damage (bodywork, levers, mirrors): The Z125 and Monkey's small size and low speed make them frequent tip-over candidates in parking lots and during slow-speed maneuvers. Bent levers, scratched bodywork, and broken mirrors are by far the most common parts needs. The Monkey's chrome fenders show scratches prominently.
Chain stretch: The small-displacement engine puts consistent load on a relatively light-duty chain. Combined with the short wheelbase and aggressive aftermarket sprocket ratios that many owners install, chain stretch and sprocket wear occur faster than on larger bikes. Check and adjust chain tension frequently; replacement intervals of 6,000-10,000 miles are typical.
Battery drain: The Z125 and Monkey use small batteries that can discharge quickly during storage or infrequent use. A battery tender is recommended for any miniMOTO that sits more than two weeks between rides. The fuel injection system draws a small standby current that accelerates discharge compared to a carbureted design.
Exhaust and intake modifications: These bikes are extremely popular modification platforms. Many used examples will have aftermarket exhaust, intake, and ECU modifications. When sourcing used OEM parts, be aware that the original airbox, exhaust, and ECU may have been swapped or modified. Stock components command a premium because of how frequently they are discarded during builds.
Commonly replaced Z125 / Monkey parts
- Bodywork and plastics (crash damage, customization)
- Chrome fenders (Monkey, scratch damage)
- Levers, mirrors, and bar ends
- Exhaust (aftermarket very popular, OEM replacement for restoration)
- Chain and sprockets
- Brake pads
- Seat (aftermarket and OEM replacement)
- Battery
Frequently asked questions
Q: Do Monkey 125, Grom, and Z125 Pro engine parts interchange
Internal engine components (piston, valves, crankshaft, oil pump) are shared across all three models. However, transmission internals depend on the gearbox configuration: the Z125 Pro and 2019-2021 Monkey use four-speed transmissions, while the 2022+ Monkey and 2022+ Grom use five-speed. Four-speed and five-speed gearbox parts do not cross. Chassis, bodywork, and frame parts are unique to each model.
Q: Will 2019-2021 Monkey 125 parts fit a 2022+ Monkey
Most bodywork and frame components interchange, but there are key differences. The 2022+ model uses a five-speed transmission (different engine cases), adds ABS (different brake hardware and wiring), and has a revised LCD instrument cluster. Verify the specific component before ordering across this generation split.
Q: Are Z125 Pro and Grom the same bike
No. The Z125 Pro and Grom share the same 124.9cc engine but use different frames, different bodywork, different exhaust routing, and different wheel configurations. The Grom has a longer wheelbase and different ergonomics. No chassis or body parts interchange between the two. Only internal engine components cross.
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