O.S. Speed 21XZ-B Spec II "Tuned" Off-Road Competition Buggy Engine

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This is the O.S. Speed 21XZ-B Spec II Tuned Off-Road Competition Buggy Engine. Since their inception, drivers around the world have equipped their vehicles with O.S. Speed engines because they demand a race-winning performance edge. The 21XZ-B Speed Spec II has been factory tuned for maximum performance, with modifications that make this power plant leaner and meaner than any XZ-B model ever produced. The Speed Spec II is engineered to deliver next level performance, and is guaranteed to give you the power you need to make it to the top of the podium.

  • Lighter DLC coated, tungsten slugged and silicone ramped crankshaft
  • Modified piston and con rod that reduces overall weight
  • Redesigned cooling head with V-shaped fins for lower CG and efficient cooling
  • 21J carburetor for smoother acceleration and better fuel mileage
  • A 6.5mm venturi is installed; 6mm and 7mm venturi's are included
0.213 cu in (3.49 cc)
Bore: 0.641 in (16.27 mm)
Stroke: 0.661 in (16.8 mm)
Practical RPM Range: 4,000-42,000
Output: 2.65 ps @ 34,000 rpm
Weight: 12.52 oz (355 g)

  • 21XZ-B Speed Spec II Buggy Engine w/21J carburetor
  • P3 Turbo Glow Plug
  • Exhaust Seal Ring
  • 6mm, 6.5mm and 7mm Venturi's
  • (2) Dust Caps
  • Instruction Manual

This product was added to our catalog on May 16, 2013.

Charles Mims
Wednesday, Jun 4 2014 (11 months ago)
O.S. Speed 21XZ-B Spec II "Tuned" Off-Road Competition Buggy Engine
This ENGINE IS awesome, what a power plant. I have 3 gallons through this engine. It is unbelievable . I have the 2060 pipe combo and this mill Will idle all day!!!! SMOOTH POWER Throughout the power band. Once again thanks OS for a reliable engine you can count on @race day.
Kah Chik Yong
Wednesday, May 15 2013 (about 2 years ago)
O.S. Speed 21XZ-B Spec II "Tuned" Off-Road Competition Buggy Engine
Awesome engine.. Use it with os pipe 2090. good range of power. easy to tune
Ricardo Mariani
Sunday, Jun 2 2013 (about a year ago)
O.S. Speed 21XZ-B Spec II "Tuned" Off-Road Competition Buggy Engine
Fantastic engine when equiped with 2060 pipe. A little smoother than the previous version but still very strong and reliable. For me it´s #1.

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