Honda CB 400 Four [1989-1991]: A Timeless Inline-Four Legacy

Introduction

The Honda CB 400 Four, sold internationally as the CB-1, represents a golden era of Japanese motorcycle engineering. Produced from 1989 to 1991, this compact inline-four machine bridges the gap between accessible middleweight performance and the mechanical sophistication that defined Honda’s reputation. While modern bikes chase horsepower figures and electronic aids, the CB 400 Four remains a testament to analog thrills – a bike that rewards skilled riders with its silky-smooth powerband, nimble chassis, and unmistakable four-cylinder soundtrack. Let’s dive into what makes this generation a cult classic and why it still resonates with riders today.

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Design & Styling

The CB 400 Four’s design is a masterclass in functional simplicity. Its naked bike silhouette features a minimalist fuel tank, a flat bench seat, and a rectangular headlight that screams late-’80s pragmatism. The 715mm (28.1-inch) seat height caters to shorter riders, while the 189kg (416.7 lbs) wet weight feels surprisingly light once on the move. Honda’s focus was clearly on usability: the narrow inline-four engine keeps the bike’s profile trim, making it easy to maneuver through city traffic or carve canyon roads.

The liquid-cooled engine is the centerpiece, with its polished cam covers and symmetrical exhaust headers hinting at the mechanical artistry beneath. Unlike today’s aggressively styled nakeds, the CB 400 Four’s aesthetic is understated – a blank canvas for customization or a nostalgic time capsule for purists.

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Engine & Performance

At its heart lies the 399cc DOHC inline-four, a jewel-like powerplant that revs to a heady 10,800 RPM. With 56 PS (41 kW) on tap, the CB 400 Four isn’t about brutal acceleration, but rather the addictive linearity of its power delivery. Throttle response is crisp thanks to its 34mm carburetors, and the 6-speed gearbox shifts with the precision of a Swiss watch.

The real magic happens above 7,000 RPM. As the tachometer climbs, the engine’s character transforms from docile commuter to a buzzing, euphoric screamer. The claimed top speed of 173 km/h (107.5 mph) feels exhilarating, not just because of the wind blast, but due to the mechanical symphony playing behind you. This is an engine that begs to be ridden hard – a trait rarely found in modern middleweights.

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Handling & Ride Quality

The CB 400 Four’s chassis is a study in balance. The 41mm telescopic forks and twin rear shocks offer a plush ride over uneven roads, yet stiffen up predictably when pushed. With a 140/70-17 rear tire and 110/70-17 front, grip levels are ample for spirited riding, though modern rubber would unlock even more potential.

At low speeds, the bike feels almost bicycle-light, thanks to its centralized mass. But it’s on twisting backroads where the CB 400 Four shines. The narrow engine allows for aggressive lean angles, and the 15/41 sprocket ratio provides snappy acceleration out of corners. Braking duties are handled by single discs front and rear – adequate for the bike’s weight, though aftermarket pads and steel-braided lines (available at MOTOPARTS.store) can sharpen response.

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Competition

In its era, the CB 400 Four faced fierce rivals:

1. Yamaha XJ600 Seca:
   The XJ600 offered more torque from its 598cc engine but weighed 30kg more. While better for touring, it lacked the Honda’s razor-sharp handling and high-revving personality.

2. Kawasaki Zephyr 400:
   Kawasaki’s retro-styled air-cooled twin appealed to traditionalists but couldn’t match the CB’s powerband breadth. The Zephyr’s vibrations at highway speeds were a notable downside.

3. Suzuki Bandit 400:
   The Bandit shared the Honda’s inline-four layout but tuned for midrange punch. However, its steel frame felt less agile, and build quality wasn’t quite as bulletproof.

The CB 400 Four carved its niche by offering race-bred engine technology in a street-friendly package – a formula that’s inspired Honda’s modern CB650R.

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Maintenance

Owning a CB 400 Four is relatively straightforward, but attention to detail pays dividends:

Valve Adjustments:
- Intake: 0.15mm (0.006") / Exhaust: 0.20mm (0.008") – cold
Stick to these clearances religiously to prevent camshaft wear.

Oil Changes:
- 3.1L of SAE 10W-40 (API SE or better). Consider synthetic blends for improved high-RPM protection.

Carb Tuning:
- The factory-recommended 2.25 turns out on the air screws is a good baseline, but altitude or aftermarket exhausts may require fine-tuning.

Chain Care:
- The 104-link chain and 15/41 sprockets demand regular lubrication. Upgrade to an O-ring chain for longevity.

Tire Pressures:
- Front: 2.25-2.5 bar (32.6-36.3 psi)
- Rear: 2.5-2.9 bar (36.3-42 psi)
Adjust for load – these bikes are sensitive to pressure changes.

Critical Upgrades:
- NGK CR8EHIX-9 iridium spark plugs improve cold starts.
- DOT 4 brake fluid refreshes every 2 years prevent spongy lever feel.
- MOTOPARTS.store carries period-correct gaskets, fork seals, and OEM-spec bearings.

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Conclusion

The Honda CB 400 Four isn’t just a motorcycle – it’s a mechanical philosophy. In an age where even entry-level bikes come laden with ride modes and traction control, this inline-four reminds us that raw, unfiltered engagement is the purest form of motorcycling. Whether you’re hunting for OEM replacement parts or performance upgrades, MOTOPARTS.store has the expertise and inventory to keep your CB 400 Four running like a watch… and screaming like a Formula 1 car at 10,000 RPM.

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Specifications sheet

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