Athena 434cc Big Bore Kit for the Suzuki DR-Z400

The Athena Big Bore Kit is a proven upgrade for riders who want more power and torque from their Suzuki DR-Z400. This complete kit increases displacement from 398cc to 434cc using a high-quality plated aluminum cylinder and a forged piston designed for durability and strong performance. The result is improved throttle response, stronger mid-range pull, and a noticeable increase in usable power without sacrificing reliability. This is a bolt-on solution with no cylinder re-plating required, making it a popular performance upgrade.

Features:

• Increases engine displacement from 398cc to 434cc

• Includes new nickel-silicon carbide plated aluminum cylinder

• Forged piston and rings designed for performance and longevity

• Bolt-on installation — no cylinder machining required

• OEM-level fit, finish, and reliability

• Improved power and torque across the rev range

• Designed and manufactured in Italy by Athena

• Easier installation as the stock crank remains. Splitting cases not needed
  

Fitment:

• 2000–2024 – Suzuki DR-Z400S

Fitment Notes:

• Kit comes with specially designed, high performance, hard anodized power valves. You cannot use the OEM valves.
• Jetting: Because this kit significantly increases displacement and air intake, you must re-jet your carburetor to prevent the engine from running lean, which can cause overheating or engine failure.
• Exhaust: To get the full potential gains of this kit, a high-flow aftermarket exhaust is highly recommended. Check your local laws for restrictions
• Does not include cylinder head.

Specifications:

• Bore Diameter: 94.00 mm (Stock is 90.00 mm)

• Displacement: 434.4 cc (Commonly referred to as 435cc or 440cc)

• Compression Ratio: 12.3:1

• Stroke: Stock crank shaft is retained with a 62.6mm stroke

Replacement gasket kit for the DR-Z400
Athena Big Bore Kit:  CLICK HERE