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Maxima MX B4 VEGAS - Competition .21 Race Engine.

  • £49900
  • Save £50

The first big appearance of MAXIMA Mx B2 engine was at The Neo Race in 2015 where Jared Tebo and Ryan Cavaliery took 1st and 2nd place as well as the fastest lap of the event. Jared Tebo during the A-main final achieved an incredible 12 minutes 30 run time. This year Jared Tebo won the NEO Race 2016 using the Mx B2R Engine using MX Fuel.

Maxima Mx B4 is based on O.S. Speed 21XZ-B spec. III engine

The engine features a newly designed crankcase, piston and cylinder and its displacement still remains at 3.49 cc (and not as 3.46cc like the Mx B2 based on Speed B2101). The engine head is 5mm lower than spec.II (Mx B2R) for lower gravity. Last improvement, the 3-port exhaust makes air flow effective after combustion. 

All units come tuned, modified and 25% pre-run in from the factory using 25% Maxima Fuel. This factory pre-run gives the engine extra performance and improved life.

If you want to add a complete exhaust system we recommend HIPEX Exhaust Systems. HIPEX is one of the best exhaust systems currently available, a brand distributed by us that fits in a perfect way with the MAXIMA Mx B4. Please check out our HIPEX COMBO Here

  • Displacement 3.49 cc/  0.213cu. in.
  • Bore 16.27 mm / 0.641 in.
  • Stroke 16.80 mm / 0.661 in.
  • Practical RPM range 4,000 – 42,000 rpm
  • Max. power output 2.65 ps / 2.61 hp / 34,000 rpm
  • Scavenging port 3-port
  • Exhaust port 3-port

Requires: glow fuel, muffler, tuned pipe and manifold


  Lighter crankshaft, with DLC coating, Tungsten weight and silicone-filled intake passage

  Modified piston and con rod that reduces overall weight

  Newly designed outer head with V-shaped fins for lower CG and more efficient cooling

  Dual-adjustable 21J carburetor for smoother acceleration and better fuel mileage

  A 6.5 mm restrictor is installed; 6 mm and 7 mm restrictors are included


Tuned and modify parts by Maxima: Sleeve, Crankshaft and Crankcase.

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