Review Axial Racing 21RR-1 engine – Part one The engine Reviews

Review Axial Racing 21RR-1 engine – Part one The engine

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Axial Racing 21RR-1 engine review.


We all know Axial Racing for their crawlers and scale trucks. I own two scale trucks and I absolutely love them. Axial is also known for their popular .28 and .32 nitro engines. A new .21 engine with race inspiration has been recently added to the Axial’s lineup. At first, I was sceptic about this engine but when I’ve read the specs and I have inspected the engine, I’ve changed my mind and I was curious and excited of getting this engine for a review.


What’s in the box:

The 21RR-1 comes in a well packaged box. The engine sits securely in foam and it is quite hard to remove the engine from the box. This has nothing to do with the engine itself but I had to told you! A 7mm venturi is already installed in the carburetor and two optional venturis (8.0 and 6.5mm) are included in the box. These venturis are extremely useful to calm down the ponies when running on loose surfaces or short tracks. They also have a big influence on runtime. If racing is not in your plans, install the 8.0mm so you can exploit all the power of the engine…But you’ll refuel a little more frequently. Also included in the box, an Axial stickers sheet and engine instructions.

Review Axial Racing 21RR-1 engine – Part one The engine Reviews

Attention, no glow plug is included with the engine. That’s the sad part of the story. Axial should include one. A glow plug should only cost them 1$ and this will have make their costumers happier. A normal glow plug will not work. This engine requires a turbo glow plug.


The engine:

The engine looks really nice. I love the black cooling head. The cross drilled fins help cooling the engine, reduce weight and give a “race” look to the engine. Under the cooling head, you’ll find the traditional turbo button head and two shims. The black coated crankcase has cross drilled fins for better cooling. Axial’s logo is painted on the engine. A composite carburetor with two needles controls the fuel/air mixture. Two rubber o-rings are installed on the carburetor neck to ensure no air leak between the carburetor and the crankcase. A removable 7mm venturi is installed at the factory.

Review Axial Racing 21RR-1 engine – Part one The engine Reviews


The internals:

When disassembling the engine, I’ve noticed that all the parts were sufficiently oiled to prevent rust and moisture between the time the engine is made and the time the engine is started for the first time. No residues of machining were found in the engine. Everything was clean and well oiled. With the cooling head removed, I’ve noticed a concave section on the piston top. I also noticed little black spots on the piston. After consulting Axial, the black spots are due to the sillicia content in the material used for the piston.

Review Axial Racing 21RR-1 engine – Part one The engine Reviews

Removing the sleeve, the piston and the crankshaft was easy. The sleeve looks like a artwork. A lot of machining and work have been done to the sleeve and it looks very aggressive. I was eager to start the engine! The crankshaft rides on non-ceramic bearings and is counterbalanced with two brass slugs to eliminate vibrations. The crankshaft’s intake section is filled with silicon for a smoother power band.

Review Axial Racing 21RR-1 engine – Part one The engine Reviews

Review Axial Racing 21RR-1 engine – Part one The engine Reviews



With an aggressive 7-port design, turbo plug and a claimed 40000 RPM, there is no doubt in my mind, the Axial 21RR-1 engine has all the potential to success on the track.

The next step will be to break in and to test the Axial 21RR-1 engine, so stay tuned to if you don’t want to miss the second part of this review!



  • Size: .21 cubic inch/3.47cc
  • Maximum RPM: 40,000
  • Bore: 15.9mm
  • Stroke: 17.5mm
  • Construction: ABC
  • Heat-sink Head: Black Anodized
  • Carburetor: 9.0mm Composite Slide Carburetor (includes 8.0, 7 & 6.5mm aluminum venturis)
  • Carburetor Adjustments: 2 Needle, Flush Settings
  • Case: Black Aluminum, Rear Exhaust
  • Connecting Rod: Dual Bushing
  • Sleeve: 7 port
  • Starting system: Bumpstart
  • Recommended Glow Plug: Turbo Glow Plug
  • Weight: 338.5g/11.94o


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Sylvain Lafrance

Sylvain Lafrance

Hello, my name is Sylvain Lafrance and I am the man behind I have bought my first hobby grade RC in the early 90s. With years, what that started as a simple hobby, quickly became a strong passion. I am so much passionate about R/C that I have created in 2006 to share my experiences with R/C products that I use for racing and bashing. Follow me !

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One thought on “Review Axial Racing 21RR-1 engine – Part one The engine

  1. This is a great review. I was looking at this engine due to the low price-point and my limited racing experience. Do you have some comments to share regarding tuning this engine and post break-in performance? I’m particularly keen to know how it stacks up against a Werks or Argus

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