Product Details

Thunder Tiger PRO .21BX-R w/Slide Carb TTR9475


Designed to achieve the easiest operation and max performance over & over, the new PRO-21BX-R delivers an awesome raw power & durability !
The new webbed reinforced compact crankcase is made for added wearing resistance and provides effective heat dispersion for longer runs.

All PRO series engines are manufactured by automated computer-controlled machinery, using the highest quality materials and state-of-the-art CNC manufacturing techniques to deliver a powerplant that looks and performs better. Precision mixture control carburetor makes adjustments simple, the crankshaft is lightened, and balanced to achieve a smoother and more efficient fuel mixture.
The new 21 engine fits in the same mounting as the original .21/.28 engines, with no additional weight - but delivers greater output and higher practical RPM.

The Pro-21BX-R is equipped with a built-in recoil starters ("X" type) for easy and quick start.

Rear exhaust
ABC construction: Aluminum piston with Cr-plated brass cylinder liner
Hypereutectic machined Al-Si ringed piston
High-strength connecting rod with bushings pre-installed
SG crankshaft
One-piece crankcase with squared-off cooling fins
Dual ball bearing-supported crankshaft
Machined over-sized heat sink head
Built-in pull starting backplate
Three-needle valves slide valve carburetor
State-of-the-art CNC machined components
Displacement: 0.213 cu in (3.49cc)
Bore: 0.661" (16.8mm)
Stroke: 0.661" (16.8mm)
Practical RPM: 3,000 - 36,000
Output: 2.15 HP @ 30,000 rpm
Weight: 16.23oz (460g)

Carburetor Settings
Needle Valve: 3 - 3-1/2 turns counterclockwise from closed
Mixture Metering Screw: After setting needle valve, 1/8 turn clockwise if mixture is too rich or 1/8 turn counter-clockwise if mixture is too lean
Height from Mounting Tab Bottom/Top of Cylinder Head: 3.7" (94.5mm)
Height from Crankcase Bottom to Top of Cylinder Head: 4.2" (108mm)
Width at Mounting Tabs: 1.8" (45.4mm)
Width of Crankcase below Mounting Tabs: 1.2" (31mm)
Center of Mounting Holes Same Side: 0.83" (21mm)
Center of Mounting Holes Opposite Side: 1.4" (36.9mm)
Center of Crankcase to Front Bearing: 1.8" (45.9mm)
Distance from Starter to Front Bearing: 3.3" (84.8mm)

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