O.S. Speed Adam Drake 4 (AD4) Engine Only(Drake Break In Service Done) - OS-1FH00D

🏁 Adam Drake Edition 4 — Engine Overview

The O.S. SPEED B21 Adam Drake Edition 4 is the latest evolution of the legendary Drake-influenced .21 off-road powerplant. Developed in direct collaboration with world-renowned racer and engine master Adam Drake, this refined edition delivers smoother power delivery, improved response, and greater consistency on the race track.

The updated 3-port cylinder liner features revised port geometry to enhance throttle feel and efficiency, while the modified crankshaft bore improves low-to-mid range response—exactly where racers need it most. The outer cooling head has been redesigned with a striking two-tone anodized finish, highlighted by Drake’s signature blue and a new laser-etched logo treatment. This engine was built to win, combining O.S. quality with Adam Drake’s proven performance insights.

Features:

• Refined 3-port cylinder liner geometry for improved efficiency
• Updated crankshaft bore for stronger low–mid power response
• Two-tone anodized cooling head with Adam Drake signature blue
• New laser-etched design for a premium look
• Incredible smoothness, consistency, and race-winning reliability
• Engine only — no pipe included

Specifications:

• Displacement: 3.49cc / 0.213 cu.in.
• Bore: 16.4mm / 0.646 in.
• Stroke: 16.55mm / 0.652 in.
• Output: 2.65 ps / 2.61 hp @ 34,000 RPM
• Operating Range: 4,000–42,000 RPM
• Weight: 352g / 12.42 oz.

Includes:

• (1) O.S. SPEED B21 Adam Drake Edition 4 Engine
• (1) O.S. SPEED T-P3 Glow Plug
• (2) Carburetor Reducers (6mm & 8mm)
• (1) Exhaust Seal Ring
• (3) Dust Caps (3mm, 16mm, 18mm)

Part Number: OS-1FH00D