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As its Thor 200 HF older brother, the Polini Thor 190HF has been developed by the R&D team using the new 3D modeling software systems and flow dynamic simulation. The result of this research and the introduction of the innovative HF System grant better cooling improving the performance of the Thor 190HF. Polini THOR 190 HF engines feature: 193cc displacement, reduced weight till 13,6 kg if equipped with Titanium exhaust system (available as an optional).


The new design of the “COVER” cooling shrouds optimizes and accelerates the incoming flows and increases the exit power towards the propeller.
Together with the air forced system it grants great performance in terms of cylinder cooling.

SCS is the innovative cooling system of the spark plug that lows the working temperatures in the point of highest warm and in the burning chamber, eliminating the events of over-heating. Polini SCS system reduces the EGT temperatures till 100 C° and till 50 C° the ones under the spark plug.

The new profile of the burning chamber improves the propagation of the flame optimizing the fuel combustion phase. This peculiarity, together with the increasing of the compression ratio, increases the engine performance reducing the fuel consumption.

Belt transmission with 2,83 reduction ratios. The belt is made of special mixture with the aim to increase the grip, to reduce the servicing, to improve the stability, life and power output.
To reduce and contains vibrations a new crankshaft with distributed and optimized rotating weights has been designed for this specific transmission system.
To resist to the belt strength, a special bearing has been housed on the transmission case side. It can stand a transversal load 10 times higher than the standard roller bearings. It lets the belt have a constant stretch.

The light alloy casting cylinder has a 193cc displacement, 64mm bore, 60 mm stroke. It offers the best performance with 29 hp of power at 8100 rpm., even with the highest working temperatures.
Its liner has a nickel-chrome coating for the best piston sliding. The piston is made of gravity die-cast light alloy at high silicon content with 2 special chromed and nitride steel rings. The new profile improves the performance and reduces the piston wear.

The exhaust system is completely hand made for a better product quality. It is divided into two sections with manifold with spherical connection and fixed on natural rubber suspensions that grant longer life. The exclusive new springs with steel hooks make them stronger and offer the possibility to be better fastened.
The exhaust system has a compact design and contained dimensions to reduce the weight. The small overall dimensions improve the aerodynamic and grant a low noise level.

Walbro carburetor with specific setting and air box. This setting, grants both a power increase at 8100 rpm and more constant power output. The Air Box with the new inlet holes grants a noise reduction and makes the setting easier.

To make the assembly on the frame easier, the frame-engine connecting points of the Polini Thor 190 HF are the same as the other engines: Thor 80, Thor 130 EVO, Thor 200 HF and THOR 250.

It is made of carbon steel material by Polini which grants longer life. To improve the fixing, M6 screws have been used.

Polini Thor 190 HF

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