RB Killer 10 .21 Review Reviews

RB Killer 10 .21 Review

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RB Products have introduced the Killer engine in 2009 (Killer 9). In 2010, they have renamed the engine for RB Killer 10.

Since the initial release of the Killer engine, the K9 and K10 engines have become very popular. The Killer engines are made in Taiwan according to the RB’s strict specifications and quality control. The engine can be bought with or without the RB 2045 tuned pipe. The street price is around 250$us for the engine and tuned pipe combo. For our review, we used the combo which represents a good deal considering the quality of the tuned pipe.

RB Killer 10 .21 Review Reviews

The K10 uses turbo plugs and a 14mm crankshaft. A composite carburetor helps to keep the fuel cool and prevent vapour lock. The Killer 10 uses 5+2 port for intake and 1 port for exhaust. A removable 8mm venturi is included with the engine.

For the photo session, I’ve completely disassembled the engine. No metal flake or residue of machining has been found into the engine. All the internal parts were oiled to facilitate the initial start and to prevent moisture or rust. The sleeve has an aggressive porting and all the parts fit tight together. No loose or play in this engine, this is a RB engine.


Break in:

The RB Killer 10 has a very tight pinch, when the piston reaches the top of the cylinder, it was impossible to turn the engine with my fingers even with the flywheel installed. To break in my new RB engine, I first used my heat gun to warm up the engine. With such pinch, heating the engine was necessary. This eliminates a lot of stress on the connecting rod and facilitates the start.

I have primed the engine by pushing air into the pressure line of the tuned pipe until fuel reached the carburetor. This greatly helps the engine to start especially for brand new engines. The Killer 10 fired up almost immediately. I had to give a little throttle to keep the engine running. The base settings were too rich for my climate, a lot of unburnt fuel was pouring out of the tuned pipe. The engine died when I released the throttle. Of course, the engine died with the piston locked on the top of the sleeve. The pinch was so tight that my LiPo powered starter box didn’t manage to spin the engine. I had to use a flat screw driver to spin the flywheel and to unlock the engine.

RB Killer 10 .21 Review Reviews

I had to lean the carburetor by closing the low and the high speed needles by almost a full turn. With those new settings, the engine was still running rich but with a better idle, the temperature was in the 180-190F. I’ve let the engine ran for almost a full tank on my starter box before I shut it off. As always, I’ve turned the flywheel until the piston reach the bottom of the sleeve and I have let the engine completely cool down for a good 15 minutes.

RB Killer 10 .21 Review Reviews

For the next eight tanks, I have always used my heat gun before starting the engine. To prevent the engine from running lean, I have stopped the engine before the fuel tank was empty. After each tank, I’ve let the engine cool down with the piston at the bottom of the sleeve. I went easy with throttle inputs. For tank #2 and #3, I only used about ¼ of the throttle and I have progressively increased the throttle input until tank #8 where I was able to use 100% of the throttle but very a very short period of time, no more than 1 second, just to clear excessive fuel. At tank #3, I’ve progressively closed the needles as needed. At tank #8, the engine was still running on the rich side with temperature in the 210-220F. You might prefer to use a different method to break in your engine. There are tons of breaking in methods, this is the one I used for all my engines and it works fine, so I keep on using it.

RB Killer 10 .21 Review Reviews

For the next fuel tanks, I’ve tuned the engine for optimal power. As always, I’ve put my temp gun far in my tool box because I prefer to tune my engines by the amount of smoke coming out of the tuned pipe, by how they respond to throttle inputs and by their sound rather than focusing on a specific temperature. Temp guns are only good to make sure your engine is not running too far out of the best operating temperature, in general between 200F and 265F.

It took me about 15 minutes to fine tune the Killer 10 engine. The RB Killer 10 is super easy to tune, its carburetor is extremely forgiving. The engine runs quite fine even if the settings are not optimal. That’s great for nitro newbies.



With one gallon of fuel burnt, the RB Killer 10 still has a good pinch and the power just get better tank after tank. I estimate the engine will reach its full potential after two gallons. Meanwhile, the RB Killer 10 engine shines in my buggy, it idles steady, it has good torque and good RPM. The throttle response is predectible, thanks to the smooth powerband. I’ll go more in details during the summer when the engine will be completely broken in after two gallons. Complete performance reports will be posted in our buggy project articles during the summer. So stay tuned to MyRCBox.com.


Specs and Features:

  • Displacement: 3.49cc
  • Bore: 16.20mm
  • Stroke: 17.00mm
  • Porting intake: 5+2 by pass
  • Porting exhaust: 1
  • Crankshaft: 14mm
  • Carburetor: Composite 8mm w/removable Venturi
  • Glowplug: Turbo 01051-6
  • Weight: 345g
  • Use: 1/8 Off Road
  • K10 crankcase with additional fins for a improved heat dissipation
  • 5 port Sleeve with 2 by-pass ports
  • Lightened conrod
  • 14mm crankshaft
  • Nylon 8mm carburetor with removable Aluminum Venturi
  • Tall cooling head for improved heat dissipation
  • Includes orange caps, instruction manual and stickers.


What I liked:

  • High quality
  • Good power and quality for the price
  • Super easy to tune


What can be improved:

  • Only one carb venturi included




Don’t let the « Made in Taiwan » fools you, the RB Killer 10 is a high quality engine. It has a smooth power band and runs flawlessly tank after tank. It has enough power to push any buggy or truggy all around any tracks. I got an average runtime slightly under 9 minutes with the RB 2045 tuned pipe. Another tuned pipe might give you a little more runtime but I can live with 9 minutes in my buggy. If you are looking for a high quality engine backed by RB reputation and service, the Killer 10 should be on the top of your list.


For more information, visit www.rb-usa.com


Sylvain Lafrance

Sylvain Lafrance

Hello, my name is Sylvain Lafrance and I am the man behind MyRCBox.com. 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 MyRCBox.com in 2006 to share my experiences with R/C products that I use for racing and bashing. Follow me !

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