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OS .21 RZ (R)

The .21 RZ - custom engineered for serious racers.

  • Pressure regulation system increases transitional throttle response.
  • Sophisticated crankshaft design blends engine performance ingenuity and high-tech CNC machine work.
  • Polished intake ports allow smoother air flow.
  • Custom shaped piston reduces weight for quicker acceleration and better cooling.
  • Con rod features lighter, more durable bushing material.
  • Crankcase backplate features an O-ring for a better seal.

More RZ performance features:

  • Insulating thermal plastic ring on carb mounting helps to hold settings and simplify tuning.
  • Large flow-thru bar stock aluminum cooling head is standard.
  • Bearings have rubber seal and larger balls for durability.
  • Cylinder features hard chrome-plated brass sleeve (ABC).
  • Carburetor stop prevents the rotor from sliding too far.
  • Mounting hole pattern matches RX Series engines for easy upgrades.
Displacement 0.211 (3.46 cc)
Bore 0.654 in (16.6 mm)
Stroke 0.630 in (16.0 mm)
RPM 3000 - 40000


2.4 BHP @ 32000 RPM
Weight 10.84 oz (307 g)
Price R Not Available