Dragon IV Edition 2 – 3 port .21 size engine (pre broken-in with injector backplate and 7.5mm bore carb)

Manufacturer: Alpha Plus



Dragon IV Version 2 engine

The new Alpha engine, the Dragon IV Version 2, is a pre broken-in, 3 port engine designed to the highest specification. The Dragon IV Version 2 continues with the Dragon III’s benefit of being easy to tune and within 2-4 tanks, be ready to race.

 With the new engine, we are able to improve the following items;

 The crankcase has been redesigned to improve the efficiency of intake and exhaust, the flow of fuel from the carburettor to the combustion chamber, and this results in less losses and greater fuel efficiency, furthermore, an increase in engine power .

 Ceramic bearings: Reduced friction, lower weight, improved longevity.

The high quality material ceramic bearings are fitted as standard to the Dragon IV, and with less drag, more energy can be applied to the wheels. It’s reduced friction, lower weight for reducing the drag, and increasing the engine power and the speed-up function.

DEC Crankshaft: Reduced engine vibration, resist wear, good lubricity.

The new version of DEC Crankshaft, has the Alpha Patent – Dynamic Equilibrium, which can efficiently balance the inertial force from piston pin, from conn-rod, and from crankshaft rotation, to reduce the vibration of engine and to increase the engine power. The timing on the crankshaft has been altered for more power and a more linear power delivery has been achieved when combined with the new piston and liner.


Redesign air intake can provide the fuel efficiency, more power and a more linear power been delivered.

Piston Pin:  The piston pin improves the hardness surface and the durability in order to reduce the possibility of bending, also made very light.

Cooling head: the new cooling head adds one more layer, but has been lowered for improved centre of gravity in order to handling of the car, whilst keeping good natural cooling effects when positioned in car.

Includes the new Injector style back plate

Includes the new Pro 7.5mm bore carburettor

Contact Us

X-Factory UK
418 St Albans Road
WD24 6PJ

Telephone: 01923 816636

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Office Hours

Mon to Wed : 10am - 5.30pm
Thursday : 10am - 7pm
Friday : 10am - 5.30pm
Sat & Sun : CLOSED 

Public Bank Holidays : CLOSED

Please note we do not supply direct to the public. Our full range of products are available via any of our UK dealers whom can be found in our dealer locator at the top of the website.