( Ø 63,0mm, cast iron, 6 ports, stroke 57mm, 2 piston ring(s), outlet 2-parts, with cylinder head, SPORT-TUNING, high-performance & roadworthy )
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( Vespa 125 GTR 2°/TS /150 Sprint 2°/V/Super 2° /PX125-150/PE/Lusso/Cosa for LML Star 125-150 2T/Deluxe )
The cylinder has a bore of 63 mm with a 178cc displacement and a completely revised internal fluid dynamics. The new siphon allows a correct coupling both with reinforced casings and with completely original casings, and provides a special profiling designed to optimize the flow and obtain considerable performance increases, even without carrying out additional work on the vehicle.
The suction decanters have a profile designed to correctly orientate the incoming flow and obtain high turbulence, thus ensuring an improvement in combustion efficiency and optimal washing. These improvements make it possible to increase combustion efficiency, reduce fresh charge losses at the exhaust and keep the temperature in the chamber within the allowed levels, even on the piston crown.
The piston Ø 63 bi-band calculated and optimized thanks to hours of testing in the test room. The piston has a profile designed to cope with the high temperatures developed in the chamber during operation, especially in the most severe conditions. Allowing the plunger to assume the correct cylindrical shape, once the working temperature is reached, it allows to obtain a more uniform sliding surface on the cast iron cylinder. Thanks to this new profile it has been possible to reduce the coupling clearance between the cylinder and the piston to guarantee greater driving in the reciprocating motion in the barrel and reduce the rotations around the pin axis, thus reducing the risk of seizure, a very dangerous phenomenon and recurrent in high performance cast iron cylinders. Even the metallic jingle, audible at the minimum and typical of this category of vehicles, has been significantly reduced. The double elastic band guarantees the correct sliding of the piston and, at the same time, a constant hold over time to the pressures developed in the chamber.
The head has been the subject of a profound revisitation starting from the cooling fins, now curved and more sinuous, able to expose a greater quantity of surface to the air and to maximize the cooling. The fin of the head has also been inserted in the gap between the head and the cylinder to generate a significant air flow able to further mitigate the operating temperature. The result is pleasing to the eye for its unique and original shape due to the accurate positioning of the fins, whose design is interrupted only when indispensable, with respect to the fixing holes of the studs. The very structure of the head has been deeply revised by increasing the mass to obtain a record-breaking rigidity, combining lightness and maximum possible length of the cooling fins and exploiting all the space made available by the conveyor. The inside of the head is hemispherical and worked with numerical control machines. The positioning of the candle is considerably inclined, while remaining central. The kit includes two centering bushes to ensure perfect coupling between head and cylinder, separated exclusively by an oring. This solution, imported directly from the world of competitions, guarantees maximum tightness and the greatest possible heat exchange, eliminating any type of gasket and thus removing any barrier between head and cylinder.