Kawasaki KH 400 (1975-1978): A Smoky Symphony of Two-Stroke Glory
Introduction
The Kawasaki KH 400 stands as a time capsule of 1970s motorcycling rebellion—a three-cylinder, two-stroke street machine that embodied the era's obsession with lightweight power and unapologetic character. Produced from 1975 to 1978, this middleweight triple carved its niche between Kawasaki's smaller 250cc offerings and the fire-breathing H1 Mach IV 750. For riders today, it represents a visceral throwback to an age when smoky exhausts and ringing engine notes were badges of honor. Let’s twist the throttle on this iconic two-stroke and see how it holds up as a classic ride.
Design & Styling: 1970s Muscle in Motion
The KH 400’s design screams "1970s" with its muscular tank lines, chrome accents, and minimalist bodywork. The teardrop fuel tank—painted in period-correct hues like Candy Red or Ebony—flows into a flat bench seat that barely accommodates a passenger, reinforcing its solo-rider focus. Chrome fenders, a squared-off tail section, and that iconic trio of expansion chambers jutting out below the engine give it a purposeful, mechanical aesthetic.
Standing beside it, you’ll notice the lack of modern clutter: no fairings, no ABS modules, just a slim analog speedometer and tachometer mounted above the headlight. The 177 kg (390 lbs) curb weight feels remarkably light by today’s standards, and the narrow 31-inch seat height makes it accessible for shorter riders. While the chrome finishes and polished engine cases demand regular cleaning, they reward owners with head-turning appeal at bike nights.
Engine & Performance: The Triple’s Howl
At its heart lies a 400cc air-cooled two-stroke triple—a configuration that delivers a unique blend of smoothness and raw edge. Output figures varied across markets due to emissions regulations, ranging from 29 kW (40 PS) in Europe to 21 kW (29 PS) in stricter regions. On the road, the powerband hits like a caffeine rush: below 5,000 RPM, it’s docile, almost sleepy. But cross that threshold, and the KH 400 transforms. The tach needle swings toward its 7,500 RPM redline as the engine unleashes a wailing crescendo, accompanied by a haze of Castrol R-scented smoke.
Acceleration is brisk rather than brutal, with 0-100 km/h (0-62 mph) arriving in around 6.5 seconds—a respectable figure even today. The three Mikuni VM20SC carburetors demand patience during cold starts (prime the oil pump with a few kicks!), but once warm, they deliver crisp throttle response. Fuel economy? Expect roughly 18-22 km/L (42-52 mpg) if ridden gently, though few owners resist the urge to chase that two-stroke high.
Handling & Ride Experience: Lightweight Agility
The KH 400’s tubular steel frame and non-adjustable telescopic forks (355 mL SAE 10W oil capacity) feel primitive next to modern suspension systems, but they enable a flickable ride. At low speeds, the narrow handlebars and 1,400 mm (55.1-inch) wheelbase make it effortless to thread through traffic. Push harder into corners, and the bias-ply tires (period-correct, though many owners upgrade to radials) communicate every ripple in the pavement.
Braking is… nostalgic. The single 180mm drum brake up front requires a firm squeeze, while the rear drum acts more as a suggestion than a command. This is a bike that rewards proactive riding—plan your stops early. At highway speeds, the lack of wind protection becomes apparent, but the KH 400 wasn’t built for touring. It’s a backroad bruiser, happiest carving third-gear bends with the exhaust howling in protest.
Competition: How the KH 400 Stacks Up
The middleweight two-stroke class of the 1970s was fiercely contested. Here’s how Kawasaki’s triple compared:
- Yamaha RD400: The KH 400’s archrival. Yamaha’s twin-cylinder offered sharper handling and a 45 PS punch, but lacked the KH’s three-cylinder smoothness. The RD’s reed-valve induction gave better low-end grunt, but the Kawasaki’s top-end rush was addictive.
- Suzuki GT380: A triple with a milder personality. Suzuki’s Ram Air cooling and quieter exhaust made it more refined, but less thrilling. The GT380’s 38 PS couldn’t match the KH’s peakier delivery.
- Honda CB400F: The oddball four-stroke. Honda’s SOHC inline-four was smoother and more reliable, but its 37 PS felt sanitized compared to the KH’s raw two-stroke theatrics.
The KH 400 carved its niche as the "wild child" of the group—less polished than the Yamaha, less practical than the Honda, but unforgettable in character.
Maintenance: Keeping the Triple Alive
Owning a KH 400 is a labor of love. As MOTOPARTS.store’s in-house classic bike expert, here’s my maintenance cheat sheet:
1. Two-Stroke Oil Matters
The oil-injection system (Kawasaki’s Auto-Lube) requires fresh 2T oil—never skip premixing 1:20 if you bypass it. We recommend MOTOPARTS.store’s Synthetic 2T Oil for cleaner burns.
2. Spark Plug TLC
NGK B8HS plugs (gap: 0.7 mm / 0.028 in) foul easily if ridden at low RPM. Carry spares and check them monthly.
3. Chain & Sprockets
The 102-link chain and 14-16/37 tooth sprockets wear quickly under hard use. Upgrade to our X-Ring chain kit for durability.
4. Carb Rebuilds
Stale fuel clogs the Mikunis. Clean jets annually and consider our Carb Repair Kit with viton seals.
5. Brake Overhaul
Drum brakes demand adjustment every 1,000 km (620 miles). Swap to our sintered brake shoes for improved bite.
6. Tire Pressure Checks
Stick to 1.7 bar (25 psi) front and 2.2 bar (32 psi) rear for optimal grip. Overinflation exacerbates the stiff ride.
7. Cooling System
No radiator? No problem. Ensure cylinder fins are clean—use our Fin Comb Tool to straighten bent edges.
Conclusion: A Time Machine Worth Riding
The Kawasaki KH 400 isn’t just a motorcycle; it’s a sensory experience. From the metallic ping of cooling expansion chambers to the way it vibrates like a tuning fork at idle, every ride feels like an event. Modern bikes may outperform it in every metric, but none replicate the raw, unfiltered joy of a two-stroke triple on the boil.
For owners, MOTOPARTS.store offers everything to keep your KH 400 alive—whether it’s OEM-spec parts or upgrades to sharpen handling. This isn’t a bike you park in a museum. It’s a machine that begs to be ridden hard, maintained religiously, and passed down to the next generation of two-stroke addicts.
Strap on a helmet, kickstart that triple, and let the smoke clear your soul.
Looking for KH 400 parts or performance upgrades? Explore MOTOPARTS.store’s curated collection of vintage Kawasaki components and expert-recommended accessories.
