Honda CM450A

Honda CM450A

The Honda CM450A launched in 1982 as a unique blend of cruiser aesthetics and commuter-friendly convenience. Marketed as the “Hondamatic” model, it distinguished itself with an automatic torque-converter transmission instead of a conventional clutch. The bike retained a compact footprint and manageable power delivery, making it approachable for new riders while still engaging for veterans. Its custom-style styling cues and reliable parallel-twin engine underscored Honda’s commitment to marrying form and function in a mid-size package.

Design and Styling

Classic Custom Influence

Honda drew inspiration from American customs when crafting the CM450A’s overall look. A teardrop fuel tank, swooping side covers, and chrome-plated exhaust endcaps delivered a laid-back cruiser vibe. Subtle pinstriping and two-tone paint options added personality without veering into ostentation. Wide, pull-back handlebars and a teardrop headlamp nacelle completed the classic profile.

Frame and Ergonomics

Underneath its cruiser façade, the CM450A uses a tubular-steel double-cradle frame that combines rigidity with compliance. The seat height sits at a low 770 mm, providing easy ground reach for most riders. A gently stepped saddle and mid-mounted footpegs promote an upright posture, minimizing fatigue on longer journeys. Cable routing and component placement emphasize accessibility for routine maintenance tasks.

Engine and Transmission

DOHC Parallel-Twin Powerplant

At its core lies a 447 cc air-cooled parallel-twin featuring dual overhead camshafts and four valves per cylinder. The engine’s bore and stroke measure 67 mm × 50.6 mm, delivering a harmonious balance of torque and top-end revs. Dual 28 mm Keihin constant-velocity carburetors ensure smooth throttle transition and consistent fueling. A compression ratio of 9.3 : 1 underpins a broad, tractable torque curve ideal for stop-and-go traffic and highway cruising alike.

Semi-Automatic Torque-Converter Transmission

In place of a traditional clutch lever, the CM450A employs a two-speed semi-automatic gearbox mated to a hydraulic torque converter. Riders shift between Low and High ranges via a foot lever, letting the torque converter handle clutch engagement. This setup removes stalling concerns and simplifies low-speed maneuvers. A manual neutral position sits between the two forward ratios for easy starting and idling.

Chassis and Suspension

Front Forks

The CM450A uses 33 mm telescopic forks with 110 mm of travel to soak up road irregularities. Sealed bushings and polished sliders help maintain smooth action and resist contamination. Fork spring and damping rates were tuned to balance confident steering response with urban-street compliance. Rake and trail figures yield predictable turn-in without feeling hesitant at slower speeds.

Rear Shock Absorbers

Twin preload-adjustable shock absorbers deliver 100 mm of wheel travel and accommodate solo or two-up riding. Progressive springs and dual damping cartridges help tame highway ripples and minor potholes. Easy-to-reach adjusters let riders dial in sag for preferred ride height and firmness. The rear suspension’s balanced compliance enhances cornering stability under power.

Brakes and Wheels

The front wheel stops via a 296 mm hydraulic disc brake paired with a single-piston caliper. This arrangement provides consistent bite, smooth lever modulation, and fade resistance in varied conditions. At the rear, a 130 mm drum brake offers dependable, weather-resistant performance with a progressive feel. Both wheels ride on 18-inch wire-spoke rims, wearing 3.00–18 front and 4.00–18 rear tires that prioritize stability and rider confidence.

Electrical System and Instruments

Ignition and Charging

A 12 V, 35 A alternator feeds a transistorized ignition module, replacing earlier mechanical systems and boosting cold-start reliability. Maintenance-free coils and a self-adjusting camchain tensioner minimize routine service intervals. The charging system supports auxiliary accessories without compromising battery health.

Instrumentation and Lighting

A rectangular headlamp nacelle houses a 55 W/60 W halogen bulb that casts a broad, even beam. The instrument cluster combines an analog speedometer with indicator lights for neutral, turn signals, and high beam. A compact tachometer sits adjacent, offering quick reference to engine speed. Flush-mount turn signals and a single-lens tail/stop lamp complete the clean, uncluttered dash layout.

Maintenance and Ownership

Routine servicing on the CM450A is straightforward: oil and filter changes every 4,000 km, valve clearance checks every 8,000 km, and carburetor synchronization at 12,000 km. The torque-converter unit requires minimal attention beyond fluid inspection at major services. Parts availability remains strong due to shared components with the CB450SC and Nighthawk series. Popular owner upgrades include braided brake lines, LED lighting conversions, and aftermarket exhaust systems to enhance sound and reduce weight.

Technical Specifications

Legacy and Conclusion

The Honda CM450A remains a testament to innovative mid-size motorcycle design, proving that automatic convenience and classic styling can coexist. Its torque-converter transmission simplified city riding, while the reliable DOHC twin delivered spirited performance on open roads. Today, well-preserved CM450As continue to attract riders who appreciate its blend of ease-of-use, low maintenance, and timeless custom flair.