| Specification | Value |
|---|---|
| Production Years | 2004-2009 |
| Engine Oil | SAE 10W-30 / 10W-40 JASO MA (0.69 L) |
| Spark Plug | NGK IMR8C-9H (Iridium) |
| Front Tire | 80/100-21 51M (1.0 bar / 15 psi) |
| Rear Tire | 100/90-19 57M (1.0 bar / 15 psi) |
| Battery | Not Applicable (Kickstart Only) |
The Honda CRF 250 R (ME10A/G) represents a pivotal moment in motocross history. When it debuted in 2004, it was the first production 250cc four-stroke to successfully implement the Unicam engine architecture. By using a single overhead camshaft to actuate both the intake valves (directly) and the exhaust valves (via a forked roller rocker arm), Honda achieved a cylinder head height and weight significantly lower than traditional DOHC designs, drastically improving the bike’s center of gravity and flickability.
Engineering Overview: The ME10 Platform
The ME10 series (2004-2009) is celebrated for its high-revving nature and precise handling. The engine features a short-stroke design with titanium valves that allow for a ceiling of 13,000+ RPM. Throughout its production cycle, Honda refined the Keihin FCR carburetor settings and exhaust geometry to broaden the powerband, making it one of the most competitive platforms in the AMA Supercross and Motocross Lites classes.
Critical Maintenance Standards
As a high-performance competition machine, the CRF 250 R demands rigorous maintenance to ensure longevity. The Unicam system, while light, requires frequent valve clearance checks to prevent hard starting and potential engine failure.
Lubrication System
The ME10 uses a split lubrication system, separating engine oil from transmission oil to prevent clutch debris from contaminating the top end. For the engine side, use 0.69 Liters of SAE 10W-30 or 10W-40 JASO MA oil. MotoSpecsLab recommends high-quality synthetic oils to withstand the extreme thermal loads of MX racing.
Ignition and Combustion
For optimal combustion and throttle response, the factory specifies the NGK IMR8C-9H iridium spark plug. This plug is designed to resist fouling during low-speed technical sections while providing a stable spark at high RPMs. Always ensure the gap is set to factory specifications before installation.
Chassis and Traction
The CRF 250 R relies on a precise balance of suspension and tire compliance. The standard setup utilizes an 80/100-21 front and a 100/90-19 rear. For most track conditions, a baseline pressure of 1.0 bar (15 psi) is recommended. Lowering the pressure slightly can increase the contact patch in soft sand, but increases the risk of pinch flats on hard-packed jumps.
MotoSpecsLab Verdict
The Honda CRF 250 R ME10A/G remains a benchmark for handling in the 250F class. While it requires a disciplined maintenance schedule—particularly regarding oil changes and valve shimming—its engineering purity and the benefits of the Unicam head make it a legendary choice for both vintage racers and modern enthusiasts.