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All Bikes/Kawasaki/Kx 450
Kawasaki Kx 450
Motocross

Kawasaki Kx 450

The Kawasaki Kx 450 has a top speed of ~145 km/h (estimated; gearing and terrain dependent — note: best estimate, not manufacturer-specified), produces ~55 hp and weighs 110 kg. Motoryk rates it 8.5/10.

カワサキのKX450(元々はKX450F)は、カワサキのラインナップで老朽化した2ストロークのKX500に代わって、2006年に4ストロークのモトクロスのライバルとして発売されました。2019 年に大幅な再設計が行われ、電動スタート、新しいフレーム、改良されたエンジン内部などが導入され、工場仕様のモトクロスマシンとして一流の評判が確固たるものになりました。KX450は複数のAMAスーパークロスおよびモトクロス選手権に参戦しており、市販されているモトクロスバイクの中でも最も競争力のある市販モデルの 1 つとなっています。

~55 hp

パワー

~52 Nm

トルク

110 kg

ウェイト

~145 km/h (estimated; gearing and terrain dependent — note: best estimate, not manufacturer-specified)

トップスピード

Estimated 6–9 L/100km (note: highly variable depending on riding intensity; off-road/motocross use is not standardized for fuel economy testing)

燃料

ボディ

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Video Review

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購入者が知っておくべきこと

⚙️

Launch Control System

The KX450 features a built-in launch control mode that limits power delivery for optimal holeshots — a feature typically found only on higher-end or heavily modified bikes.

🔧

Watch the Valves

Valve clearance can tighten faster than expected under hard use, so budget for inspections every 30-40 hours to avoid costly engine damage — a common oversight among used KX450 buyers.

💰

Strong Resale Value

The KX450 holds its value well compared to competitors, largely due to Kawasaki's reputation for durability and the bike's consistent podium presence in professional motocross.

年別の世代と仕様

2006–2008 Gen 1

アルミフレームのKX450F、449ccの水冷4ストローク、燃料噴射の前身であるキャブレター付きセットアップを導入。

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8.2/10

"4ストロークのモトクロスを作り直した、未加工のアルミフレーム武器。"

カワサキが2006年にKX450Fを発売したとき、そのアルミニウム製の外周フレームは、これは暖められた強打ではなく、真に考え直されたことをすぐに教えてくれました。449ccのDOHCモーターはミッドレンジから強く引っ張られ、7,000 rpmを超えると完全に爆発します。狭いわだち掘れしたトラックで腕をポンピングして、両端を入れ替えるまでは素晴らしい音です。サスペンション、特にカヤバSSSフォークは、私が背中合わせに乗ったHonda CRF450Rよりもスクエアエッジのヒットを吸収して、その時代において真にクラスをリードしていました。正直なところ、初期のユニットの炭水化物は工場から低く排出されていたため、底部から厄介なフラットスポットが発生し、第1世代のスロットルレスポンスは、スムーズでなければミッドコーナーで追いつかれるほど急激でした。

プロ

+硬くて精密なアルミフレーム
+トップエンドのパワーは本当に印象的です
+カヤバSSSフォーク発行済株式
+時代に合わせた競争力のあるウェットウェイト
+強力なアフターマーケットサポートも引き続きご利用いただけます

短所

リーン・ファクトリー・ジェッティングには即時の修正が必要
突然の電力供給は、だらしないライダーを罰する
ハイシートは背の低いライダーを怖がらせる
こんな方に最適: 表彰台を追いかける経験豊富なモトクロスライダー 次の場合はスキップ: 4ストロークモトクロスは初めて
2009–2011 Gen 2

フレーム形状の改訂、新しいサスペンション設定、シリンダーヘッドとエキゾーストの更新により、パワーデリバリーが向上しました。

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2012–2015 Gen 3

新しいアルミニウムフレーム、改良されたエンジン内装、電動スターターの追加、エルゴノミクスの改善、燃料噴射装置の更新。

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2016–2018 Gen 4

改良されたフレーム、更新されたサスペンション、新しいボディワーク、改訂されたエンジンマッピング、ローンチコントロールが導入されました。

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2019–2021 Gen 5

フィンガーフォロアバルブトレイン、新しいフレーム、油圧クラッチ、最新の燃料噴射、大幅な軽量化。

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2022–2025 Gen 6

新しいシャーシ、更新されたサスペンションリンケージ、改良されたボディワーク、トラクションコントロール、改良されたエンジン性能と電子機器。

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中古購入者レビュー

8.5/10
こんな方に最適
Experienced motocross riders ready for serious competition

"A brilliant 450 that rewards experienced riders who buy smart."

$5,500-$8,500 used

The KX450 is a serious piece of machinery, and buying one used means you're inheriting someone else's maintenance habits — for better or worse. These engines are built tough, but they're also built to be flogged hard, so the first thing you're checking is service history. Valve clearances, hour meters, whether the air filter's been swapped regularly. A neglected KX450 will bite you financially before it bites you on the track. Get a good one, though, and you've got one of the sharpest-handling 450s on the market. The power delivery is explosive but manageable once you're comfortable with it — not the friendliest bike for intermediate riders stepping up in class. The suspension is legitimately excellent stock, which saves you money compared to competitors that need immediate respringing. Kawasaki's launch control and traction management systems on newer models are genuinely useful, not just marketing fluff. Price is fair in the used market right now. Just budget for consumables — chains, sprockets, and brake pads disappear fast on a bike that gets ridden the way this one deserves.

プロ
短所
次の場合はスキップ: Intermediate riders still building fundamental skills

Top 10 Accessories

Curated picks for the Kawasaki Kx 450 — owned, ridden, recommended.

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よくある問題

🔥 1 CRITICAL
🔥Worn piston and cylinder from high hours SERIOUS

Compression test, inspect for smoke or rattling noise

Fix cost: $300-$600
⚠️Valve clearance issues causing hard starting MODERATE

Cold start behavior, ask when valves last checked

Fix cost: $150-$400
⚠️Worn suspension linkage and bearings MODERATE

Grab rear wheel, check for play and clunking

Fix cost: $100-$300

購入前チェックリスト

Request full maintenance and rebuild history
Check frame for cracks near steering head
Inspect sprockets and chain for wear
Start cold, listen for top-end ticking

Reliable if maintained, high risk when neglected

Full Specifications

Engine Power ~55 hp @ 9,000 rpm (estimated; Kawasaki does not officially publish power figures — note: dyno results typically range 53–58 hp)
Torque ~52 Nm @ 7,500 rpm (estimated; official figures not published — note: best estimate based on dyno data)
Top Speed ~145 km/h (estimated; gearing and terrain dependent — note: best estimate, not manufacturer-specified)
Weight 110 kg (curb weight, 2023 model)
Fuel Consumption Estimated 6–9 L/100km (note: highly variable depending on riding intensity; off-road/motocross use is not standardized for fuel economy testing)
Type Motocross
Fairing No Fairing (Naked)

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Compare Kawasaki Kx 450 Side-by-Side

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Community Reviews

Discussion

Frequently Asked Questions

What are common problems with the Kawasaki Kx 450? +

Worn piston and cylinder from high hours: Compression test, inspect for smoke or rattling noise (serious) | Valve clearance issues causing hard starting: Cold start behavior, ask when valves last checked (moderate) | Worn suspension linkage and bearings: Grab rear wheel, check for play and clunking (moderate)

Is the Kawasaki Kx 450 a good motorcycle? +

A brilliant 450 that rewards experienced riders who buy smart. Rating: 8.5/10. Best for: Experienced motocross riders ready for serious competition. Avoid if: Intermediate riders still building fundamental skills.

What is the horsepower of the Kawasaki Kx 450? +

The Kawasaki Kx 450 produces ~55 hp @ 9,000 rpm (estimated; Kawasaki does not officially publish power figures — note: dyno results typically range 53–58 hp), with ~52 Nm @ 7,500 rpm (estimated; official figures not published — note: best estimate based on dyno data) of torque. Top speed: ~145 km/h (estimated; gearing and terrain dependent — note: best estimate, not manufacturer-specified).

Is the Kawasaki Kx 450 good for beginners? +

Not really — the Kawasaki Kx 450 is better for experienced riders. Experienced motocross riders ready for serious competition Avoid if: Intermediate riders still building fundamental skills

Is the Kawasaki Kx 450 reliable? +

Owners report 1 critical issue to watch for on the Kawasaki Kx 450, notably: Worn piston and cylinder from high hours (Compression test, inspect for smoke or rattling noise). Buy with a pre-purchase inspection.

Is the Kawasaki Kx 450 good for daily use? +

Experienced motocross riders ready for serious competition Fuel: Estimated 6–9 L/100km (note: highly variable depending on riding intensity; off-road/motocross use is not standardized for fuel economy testing).

How fast is the Kawasaki Kx 450? +

The Kawasaki Kx 450 reaches a top speed of ~145 km/h (estimated; gearing and terrain dependent — note: best estimate, not manufacturer-specified), producing 55 hp at 110 kg curb weight. Real-world performance depends on rider weight, gearing, and road conditions.

What gear should I buy for a Kawasaki Kx 450? +

Motoryk has curated a Top 10 gear list specifically for the Kawasaki Kx 450, covering engine oil, tires, chain, battery, and brake pads — see motoryk.com/bikes/kawasaki/kx-450/top10. Each pick is matched to this bike's spec.