A unique engineering highlight of the Honda CRF 250 RX is that it was the first Honda 250cc machine to successfully bridge the gap between pure motocross aggression and endurance-focused versatility by utilizing a dedicated ECU mapping strategy—specifically designed to manage the Unicam® engine’s power delivery for better traction on slick, technical trails compared to its ‘R’ sibling.
| Specification | Data |
|---|---|
| Model Series | ME12A / ME12L / ME12RX |
| Production Years | 2019 – Present |
| Engine Oil | SAE 10W-30 JASO T 903 MA (Pro Honda GN4) |
| Oil Capacity | 1.0 L – 1.1 L |
| Spark Plug | NGK SILMAR9A-9S |
| Battery | Eliiy Power HY85S (Lithium-Ion) |
| Front Tire | 80/100-21 51M |
| Rear Tire | 110/100-18 64M |
| Standard Pressure | 1.0 bar (15 psi) Front/Rear |
Technical Overview
The Honda CRF 250 RX (ME12 series) represents the pinnacle of Honda’s ‘Absolute Holeshot’ philosophy adapted for GNCC and Hare Scramble competition. Unlike the motocross-specific CRF 250 R, the RX variant features an 18-inch rear wheel, a larger fuel tank, and specifically tuned Showa suspension components to absorb the high-frequency chatter found in off-road environments.
Maintenance Essentials
Lubrication System
For the ME12 series, Honda specifies SAE 10W-30 JASO T 903 MA oil. Using the Pro Honda GN4 or an equivalent high-performance synthetic is critical for protecting the high-revving valvetrain. The oil capacity ranges from 1.0 liter for a standard drain to 1.1 liters if the filter is replaced or the engine is dry.
Ignition & Electrical
The engine utilizes a high-performance NGK SILMAR9A-9S laser iridium spark plug. This plug is designed to withstand the extreme heat cycles of competitive racing. To keep the weight centralized and low, Honda employs the ultra-lightweight Eliiy Power HY85S Lithium-Ion battery, which requires a LiFePO4-compatible charger for maintenance.
Chassis & Handling
The RX comes standard with a 21-inch front and an 18-inch rear wheel setup. The 18-inch rear (110/100-18 64M) provides a larger sidewall, which is essential for impact absorption over roots and rocks. For optimal performance across mixed terrain, a baseline pressure of 1.0 bar (15 psi) is recommended for both the front and rear tires.
Editor’s Verdict
The CRF 250 RX is a masterclass in balance. By retaining the frame and engine architecture of the motocross model but softening the edges where necessary, Honda has created a machine that is as capable of winning a national enduro as it is a local track day. Proper adherence to the 10W-30 oil specification and spark plug maintenance is vital for ensuring the longevity of this high-strung racing engine.