ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)

Read Reviews
5 (5)
Write a Review
With your purchase, receive at no cost:
BSG Kicker Button

This is the ProTek R/C 321B "Samurai" Off-Road 3-Port Competition Buggy Engine. The 321B “Samurai” Off-Road 3-Port engine is ready to lead you into battle – a samurai, by definition, is a noble, powerful warrior willing to serve his master – with a short-stroke, turbo head, rear ceramic bearing and legendary, easy-to-tune carburetor, it’s easy to see why the ProTek racing engine bears the Samurai moniker!

The Samurai sips fuel without sacrificing horsepower thanks to elliptical aluminum carburetor restrictors that are included. The handcrafted powerhouse has been built meticulously by a world-renown Japanese engine manufacturer, to the specs of’s top pro drivers.

The Samurai delivers a versatile package like no other – excellent fuel mileage, predictable, crisp throttle-response and consistent carburetor settings are all traits every racer needs to stand atop the podium – to be crowned the master of his class.

The Samurai 321B has been meticulously designed and crafted in Japan by a leading maker of model engines. It has been manufactured in limited production runs guided by nearly 80 years of experience and an unrelenting commitment to both quality and performance.



  • Superior tunability
  • Low CG cooling head
  • Increased fuel mileage
  • Unrivalled power
  • Smooth and responsive power band
  • Custom 7 & 8mm elliptical restrictors
  • Ceramic rear bearing
  • ABC piston and cylinder
  • Ultra hot ProTek P3 turbo glow plug
  • Strengthened black-coated crankcase

Recommended Exhaust:

  • PTK-2060: ProTek R/C 2060 Tuned Pipe w/Manifold (PTK-2060-1: pipe only)
  • PTK-2090: ProTek R/C 2090 Tuned Pipe w/Manifold (PTK-2090-1: pipe only)

Recommended Glowplug:

  • PTK-2542: ProTek R/C P3 Turbo Glow Plug (Ultra Hot)

3.46cc (
16.6mm (0.654in.)
Stroke: 16.0mm (0.630in.)
Practical R.P.M.: 3,000 - 40,000
Power Output:
2.5ps / 34,000 R.P.M.
355g (12.52oz)


  • (1) 321B "Samurai" Off-Road Buggy Engine
  • (1) P3 Turbo Glow Plug (Ultra Hot)
  • (1) High Temp Exhaust Gasket
  • (1) 7mm "Elliptical" Aluminum Carburetor Restrictor 
  • (1) 8mm "Elliptical" Aluminum Carburetor Restrictor
  • (3) Dust Caps (3mm, 16mm & 17mm)
  • (1) Instruction Manual

This product was added to our catalog on August 20, 2014.

Dan Hissam
Verified Owner
Sunday, Nov 9 2014 (6 months ago)
ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)
This motor is very impressive and has the perfect balance of power/runtime/ease of tuning and reliability. The folks at Amain knew what they wanted in a top level engine and the performance is second to none. The power is robust, yet very smooth and never runs on. The ease of tuning is also unrivaled. This mill inspires confidence, has a very stable idle and is extremely forgiving to tune. Serious sportsman drivers all the way up to pros will appreciate the linear power and consistency. Thank you Amain for bringing this level of performance and ease of use back to us! Settings: (These are my finalized settings AFTER break-in and 1 gallon of fuel) use the recommended break-in procedure in manual!!!!!!!! Samurai 321 Altitude: sea level-1500ft. Ambient temp: 75-80*F Buggy: Mugen MBX-7 Fuel: Nitrotane 30% Plug: O.S. P3 (included) carb restrictor: 8mm (included) Pipe: O.S. 2090 or O.S. 2050 Header: O.S. M2000 Head Clearance (factory setting) Idle: flush (factory setting) low Speed: flush (factory setting is 0.5mm OUT from flush) Mid Speed: (0.10mm in from flush) 3-4 hours leaner than factory setting High Speed: 1.20mm in from flush
Bobby Pettit
Friday, Oct 3 2014 (7 months ago)
ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)
I pitted for Chris Chim at the Worlds in Sicily and he was running this engine. They had a speed gun clocking the cars as they came down the straight. His motor was constantly as fast or faster than any car. It dropped straight to idle when he let off the throttle and fuel mileage was equal to everyone's. This motor is impressive!
Jeff Stroup
Verified Owner
Sunday, Sep 7 2014 (8 months ago)
ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)
This motor is just incredible. I broke it in a Friday before a weekend long tournament and it could not have went smoother. I ran it all weekend with no issues what so ever including no flame outs. This thing has crazy amounts of power from bottom to top end. Compared to my jq engine its easier to tune and has better fuel mileage. Overall I couldn't be more satisfied. Just buy a few spair p3 plugs and a protek 2060 pipe and your set!
Austin Blair
Wednesday, Sep 3 2014 (8 months ago)
ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)
This motor is unbelievable! So much power at your finger tip, amazing fuel millage, super easy to tune, and has a ton of top end. What more could you ask for? You wont have to worry about not being able to clear a big triple anymore.
jeremy de coster
Monday, Aug 25 2014 (9 months ago)
ProTek RC 321B “Samurai” Off-Road 3-Port .21 Competition Buggy Engine (Turbo Plug)
Yayy an O.S. speed for 50$ less + you get a cool wooden box. Im in!

Related Products

FREE Shipping Eligible!

Price: $399.99 (Save 20%)
Sale: $319.99
In Stock!
This item is eligible for Super Saver Shipping Learn More
This item earns up to 320 VIP Reward Points Learn More

Manufacturer Info

Browse other products from ProTek RC