Cylinder Malossi 166 cc cast iron for Vespa PX 125-150 - What 125 - GTR - TS

Cylinder Malossi Ø 63 IN CAST IRON FOR VESPA COSA - PX 125-150 CC INSIDE YOU WILL FIND THE COMPLETE SI 20 VES. PX CVF COD.68 4013 EMULSIONATOR BE3 MINIMUM THROTTLE 52/140 MAX THROTTLE 115-105 THERMAL UNIT Ø 63 IN CAST IRON CYLINDER The cylinder has a bore increased to 63 mm with a displacement of 178cc and completely revised internal fluid dynamics. The new decanting allows for correct coupling both with joined crankcases and with completely original crankcases, and features a special profiling designed to optimise flow and achieve significant performance increases, even without performing additional machining on the vehicle. THROUGH-TRAVERS The intake manifolds feature a profile designed to correctly orientate the inlet flow and achieve high turbulence, thus ensuring improved combustion efficiency and optimum scavenging. These improvements make it possible to increase combustion efficiency, reduce fresh charge losses at the exhaust and keep the temperature in the chamber within permissible levels, including at the piston crown. The rear transfers have been the subject of an in-depth study that has led to the definition of an innovative profile with double inclination (1-2) which, by exploiting the well-known Coanda effect, allows a greater flow rate compared to traditional type rear transfers, while differentiating the orientation of the jet from the single combustion chamber inlet port: in this way it has been possible to reduce short-circuits of fresh charge at the exhaust and simultaneously increase the amount of fresh mixture introduced. The exhaust has also undergone a thorough overhaul and features a new, wider valve timing and a redesigned profile to ensure the correct flow of gases exiting and directed towards the muffler. Ø 63 PISTON The Ø 63 bi-stage piston has been calculated and optimised 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 under the harshest conditions. Allowing the plunger to assume the correct cylindrical shape, once the operating temperature has been reached, provides a more uniform sliding surface to the cast iron cylinder. Thanks to this new profile, it has been possible to reduce the clearance between the cylinder and piston to ensure greater guidance in the alternating motion in the barrel and reduce the rotations around the piston axis, thus reducing the risk of seizing, a very dangerous and recurring phenomenon in high-performance cast iron cylinders. Even the metallic rattling, audible at idle and typical of this category of vehicles, has been significantly reduced. The double piston ring guarantees correct piston sliding and, at the same time, constant resistance over time to the pressures developed in the chamber. HEAD The head has undergone a thorough overhaul starting with the cooling fins, which are now curved and more sinuous, exposing more surface area to the air and maximising cooling. The fins of the head have also been inserted into the cavity between the head and cylinder to generate a significant flow of air, further mitigating the operating temperature. The result is pleasing to the eye due to its unique and original shape resulting from the careful positioning of the fins, the design of which is only interrupted when indispensable, in relation to the stud holes. The structure of the head itself has been profoundly revised by increasing the mass to achieve record-breaking rigidity, combining lightness with the 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 machined with numerically controlled machines. The positioning of the spark plug is considerably inclined, while remaining central. The kit includes two centring bushings to ensure perfect coupling between head and cylinder, separated only by an oring. This solution, imported directly from the world of racing, guarantees maximum tightness and the greatest possible heat exchange, eliminating any type of gasket and thus removing any barrier between head and cylinder. 3117676 Ø 63 mm Use Urban / sport Power range 14 / 22 Tuning level easy Recommended carburettor Si 24/24 phbh 30 Stroke 57 Compression ratio 1:10,5 N° segments 2 N° ports 6 Hemispherical head Spark plug iw f 27