Novarossi KEEP OFF .21-7XL 7-Port .21 Off Road Engine w/Ceramic Rear Bearing (Turbo)

Read Reviews
5 (2)
Write a Review

This is the Novarossi KEEP OFF .21-7XL 7-Port .21 Competition Off Road Engine. The KEEP OFF includes all the tricks and tweaks that Novarossi has developed for their off-road engines, most notably a unique and patented bearing design that reduces the inertia of the rotating mass and increases the engines scavenging, delivering increased throttle response and higher top speed. This, combined with a unique crankshaft, and a patented 7-port sleeve deliver maximum performance. Additionally, the Evolution 2 cooling head was chosen to keep the cooling head mass as low as possible, and the re-designed exhaust gasket helps to increase the life of the gasket.


  • Cooling Head: The 'Lighter & Lower Evolution 2' cooling head has been drilled and milled out to reduce the mass of the cooling head, lowering the Center of Gravity of the engine/car.         
  • Sleeve: The sleeve has 7 transfer ports, and an exhaust with booster ports. The patented port shape and positioning improves the internal fluid dynamics to deliver maximum performance.
  • Crankshaft: The crankshaft has a special shape to reduce turbulence in the crankcase, while the front part was extended to improve the seal and prevent leaking.
  • Gasket: The inner shape of the gasket has been redesigned to allow the use of more material and when combined with an updated material is more resistant to high temperatures.
  • Conrod: The R7 conrod is machined from a super light aluminum that has been checked ultrasonically. The unique shape of the R7 rod creates less turbulence inside the engine.
  • Backplate: The shape of the rear cover helps to optimize the crankcase filling and reduces dead space. The steel plate helps to reduce friction and increases the life of the rod.
  • Carburetor: The carburetor of this engine is made from plastic and in "reverse" style, with a sliding throttle valve. The updated three tuning needles gives a better idle and improves the ability of the engine to return to low rpm after throttling.
  • Rear Ball Bearing: The ceramic rear ball bearing reduces the inertia of the rotating mass and increases the engine's scavenging ability. The bearing, combined with the re-designed case provide increased throttle response and higher top speeds.
Recommended Tuned Pipes: 51006M, 51016, 51020M
Recommended Manifolds: 41021, 41029, 41030

Recommended Glow Plug:
  • C5TGC: For ambient temperature - 32F/50F (0C/10C)
  • C6TGC: For ambient temperature - 50F/77F (10C/25C)
  • C7TGC: For ambient temperature - 77F/104F (25C/40C)
Displacement: 3.49 cc
R.P.M. (max power): 36,800 RPM
Practical Range: 6,000-40,000 R.P.M.
Bore x Stroke: 15.88x17.60mm
Sleeve: 7 ports
Rear Ball Bearing: ceramic
Front Ball Bearing: steel
Crankshaft: 14.5mm - turbo 
Carburetor: plastic - 9mm - slide
Glowplug: Turbo (C6TGC)
Exhaust Position: rear
Weight: 370g
Fuel type: 25% nitro

This product was added to our catalog on May 22, 2013.

Brandon Siegel
Tuesday, Jan 7 2014 (about 2 years ago)
Novarossi KEEP OFF .21-7XL 7-Port .21 Off Road Engine w/Ceramic Rear Bearing (Turbo)
Outstanding truggy engine! Recently retired my Bonito XLB to back up duty and installed the Keep Off 21-7 XLS in my Serpent 811T. Better bottom/mid compared to Bonito with a top end that keeps on pulling strong. Using 9901SS pipe, 41021 header and C6TGC plug on 30% VP/PM fuel.
Jim Niemer
Thursday, May 22 2014 (about a year ago)
Novarossi KEEP OFF .21-7XL 7-Port .21 Off Road Engine w/Ceramic Rear Bearing (Turbo)
Its the same engine as a bonito with a different main bearing, do not like the mid range spraybar, was way off at factory settings, I recommend to use a two needle carb, I put one on and the engine ran fine, the transition from low to high was much better with a standard carb. The engine is nothing spectacular but it does run very well.

Related Products

This item is discontinued and no longer available for purchase. You may want to search our site for a similar item.
Stock Notification

Please Log in to receive a notification when this item arrives in stock.

Manufacturer Info
Browse other products from Novarossi