| Specification | Data Detail |
|---|---|
| Model Series | ME10A/A |
| Production Years | 2004-2009 |
| Engine Type | 249cc Liquid-Cooled Unicam 4-Valve |
| Engine Oil Capacity | 0.66 Liters |
| Transmission Oil Capacity | 0.60 Liters |
| Oil Grade | SAE 10W-30 JASO T 903 MA |
| Spark Plug | NGK R0401B-8 |
| Tire Size (Front/Rear) | 80/100-21 51M / 100/90-19 57M |
| Tire Pressure (Cold) | 1.0 bar (15 psi) |
| Ignition Type | Kick-start / CDI (No Battery) |
Engineering Heritage: The Unicam Advantage
The Honda CRF 250 R (ME10A/A) represents a pivotal moment in motocross history. When Honda transitioned from the dominant CR250 2-stroke to the CRF 4-stroke platform, they introduced the Unicam valve train. Unlike traditional Double Overhead Cam (DOHC) designs, the Unicam uses a single camshaft to directly actuate the intake valves while using a forked low-friction roller rocker arm for the exhaust valves. This engineering choice allowed for a significantly more compact cylinder head, lowering the center of gravity and reducing overall engine weight—a critical factor for the ME10A’s legendary flickability in corners.
Maintenance Protocol: Dual-Lubrication System
One of the most distinctive technical features of the ME10A/A is its split lubrication system. By separating the engine oil (0.66 L) from the transmission oil (0.60 L), Honda ensured that clutch debris and transmission shavings never contaminate the sensitive engine internals or the high-revving valve train. For peak performance, MotoSpecsLab recommends Pro Honda GN4 or HP4 (SAE 10W-30). Using a JASO T 903 MA certified oil is non-negotiable to prevent clutch slippage and maintain the integrity of the friction plates.
Ignition and Spark Management
The ME10A/A utilizes a specialized racing plug: the NGK R0401B-8. This is not a standard consumer plug; it is designed to withstand the extreme cylinder pressures and high RPMs of competitive motocross. Because the bike lacks a battery and relies on a CDI ignition system powered by a kick-start, maintaining a clean, properly gapped plug is essential for consistent cold-starting and preventing high-RPM misfires.
Chassis & Wheel Dynamics
The ME10A chassis is tuned for precision. The factory tire configuration—80/100-21 at the front and 100/90-19 at the rear—is optimized for a balance between traction and agility. Maintaining a consistent 1.0 bar (15 psi) is the standard baseline; however, professional riders often adjust this by +/- 2 psi depending on track density (soft vs. hard-pack). The lack of an electric start (and thus a battery) keeps the dry weight at a minimum, staying true to Honda’s ‘Mass Centralization’ philosophy.
Frequently Asked Questions
Does the CRF 250 R (2004-2009) have a battery?
No, the ME10A/A is a kick-start only model and does not utilize a battery, relying instead on a high-output CDI ignition system.
Can I use the same oil for the engine and gearbox?
While you can use the same grade (10W-30 JASO MA), you must fill them into their respective separate reservoirs. The engine takes 0.66L and the transmission takes 0.60L.