| Feature | Specification |
|---|---|
| Production Years | 1982 – 1984 |
| Engine Type | SOHC Parallel Twin, 233cc |
| Engine Oil | SAE 10W-40 (API SE/SF) – 1.3 Liters |
| Spark Plug | NGK CR7HS (Gap: 0.6 – 0.7 mm) |
| Tire Size (Front) | 3.00 – 18 47P |
| Tire Size (Rear) | 110/90 – 16 59P |
| Battery Type | YB9-B (12V) |
While often overshadowed by the later ‘Rebel’ series, the Honda CM 250 C (MC06) holds a distinct place in motorcycle history as the primary engineering donor for the CMX250. It introduced the ultra-reliable 233cc 360-degree crank parallel-twin engine architecture that would remain in Honda’s global production for over three decades, a testament to its thermal efficiency and mechanical simplicity.
Technical Engineering Overview
The MC06 was designed during the height of the ‘Custom’ movement. Unlike the high-revving sportbikes of the era, the CM 250 C focused on low-to-mid range torque. The Single Overhead Cam (SOHC) design utilized a chain-driven camshaft and screw-type valve adjusters, making it one of the most accessible platforms for home mechanics. The engine’s characteristic 360-degree firing order provides a unique exhaust note and smooth power delivery at lower RPMs, though it relies on rubber engine mounts to mitigate secondary vibrations.
Maintenance Guide & Service Essentials
1. Lubrication System
The CM 250 C utilizes a wet sump system. For optimal protection of the integrated gearbox and wet clutch, use 1.3 liters of SAE 10W-40 oil. Ensure the oil meets API SE or SF standards. Because this engine lacks a high-efficiency spin-on filter (relying instead on a centrifugal cleaner and internal screen), frequent oil changes every 2,000–3,000 miles are critical for longevity.
2. Ignition and Electrical
The heart of the combustion cycle is the NGK CR7HS spark plug. To ensure consistent flame kernel growth, the gap must be precisely set between 0.6 and 0.7 mm. Electrical stability is provided by the YB9-B battery; given the age of these machines, checking the charging system’s regulator/rectifier output is a mandatory diagnostic step during annual service.
3. Chassis and Tires
The MC06 uses a staggered wheel setup to achieve its cruiser stance. The front requires a 3.00 – 18 47P tire, while the rear utilizes a 110/90 – 16 59P. Proper inflation is vital for handling stability:
- Front: 2.0 bar (28 psi)
- Rear (Solo): 2.0 bar (28 psi)
- Rear (With Passenger): 2.25 bar (32 psi)
MotoSpecsLab Verdict
The Honda CM 250 C (MC06) is a masterclass in ‘UJM’ (Universal Japanese Motorcycle) philosophy adapted for the cruiser market. Its over-engineered powertrain and straightforward maintenance requirements make it an ideal candidate for vintage enthusiasts. By adhering to the specified 1.3L oil capacity and precise spark plug gapping, owners can ensure this 1980s icon remains roadworthy for decades to come.