O.S. Speed B21 AD2 Adam Drake 2 .21 Competition Nitro Engine


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The O.S. Speed B21 AD2 Adam Drake 2 Engine was designed and developed in collaboration with the man, the myth, the legend - Adam Drake. "The Drake" is a true master of his craft, and the B21AD2 engine has several choice updates specified by Adam. Based off the B21AD, the B21AD2 features a unique crankshaft, cooling head and head button with an o-ring to reduce vibration and keep dirt out, as well as an updated carburetor ball, and different size venturi.

Featuring a semi-long stroke configuration, this engine boasts a DLC crankshaft with larger double tungsten counterweights and a unique cylinder design that’s exclusive to the Drake edition engines. These changes will provide smoother low end power and more overall torque than the previous model. The AD2 is an excellent choice for both buggy and truck racing as it provides a linear power band, exceptional fuel mileage and tons of overall power.

Recommended Pipe and Header for the AD2 Engine:

  • Buggy: 2100SC pipe and 75mm manifold
  • Truck: 2090SC with 85mm manifold 


  • Adam Drake’s unique engine specs not used on any other O.S. Speed engine
  • Great for buggy and truck racing
  • Redesigned cylinder liner with optimized porting
  •  DLC crankshaft with larger double tungsten counterweight
  • Semi-long stroke configuration
  • Blue anodized 6.5 and 7.0 mm carburetor reducers
  • Ceramic rear bearing
  • 21J carburetor
  • O.S.SPEED P3 gold plug, great for medium and low speed torque performance, is also included

Bore: 16.4mm / 0.646 in.
Displacement: 3.49cc / 0.213 cu.in.
Engine (Only) Weight: 353g / 12.45oz
Power Type: Glow
HP: 2.61 HP / 34,000 rpm
RPM Range: 4,000 - 42,000
Stroke: 16.55 mm / 0.652 in. output


  • (1) AD2 Engine
  • (1) Engine to Header Gasket
  • (1) P3 Gold plug
  • (1) 21J carburetor
  • Blue anodized 6.5 and 7.0 mm carburetor reducers

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