Polini evolution 70cc complete engine, p.r.e. version prepared for disc brake. Polini code: 050.0947
Polini 70cc engine for Piaggio Zip 50cc 2t Sp H2O from 2001
Polini 70 cc engine for Piaggio Zip 50cc 2t Sp H2O from 1996 to 2000
Polini 70cc engine for Piaggio Zip SP, developed with very advanced MotoGP solutions, is aimed at real riders.
Polini Evolution Crankcase for Zip SP with 10 "wheel rims was born from an articulated study that does not stop only with the construction of the crankcase, but is a related application of the entire engine unit with all the various integrated parts.
Two versions available:
70cc with bore and stroke of 47.6 by 39.3.
100cc with bore and stroke of 50 by 50.
Countless technical features:
Ground cast light alloy crankcase designed with a new engine support to optimize the shape of the exhaust exiting the cylinder. The support is mounted with two bearings that stiffen the frame and improve resistance to twisting.
There will be two exhaust systems available rigorously hand-built in special steel: one for the 70cc engine and one for the 100cc engine.
Enlarged and oversized bearing seats with particular characteristics for housing larger diameter and width motor shafts. There are two shafts available based on the displacements.
Larger seat of the intake reed valve to allow the use of carburetors from 19 mm to 28 mm or with even larger diffusers. The thickness of the valve's carbon reeds will be specific based on the engine displacement.
Flange cylinder fixing system. Two water-cooled light alloy cast cylinders, one Ø47.6 and one Ø50 directly derived from the Polini 125 GP engine that competed in the World Speed Championship. Internal passage of the coolant
by means of the Close Deck system. Barrel with nickel-silicon coating. Five transfer ports characterized by a particularly performing diagram. Exhaust port with crossbar
central to optimize the evacuation of exhaust gases. Gravity cast piston in light alloy with high silicon content with chromed segment.
The head is the one used in the 125 GP engine with 6 screws fixing, squish and dedicated combustion chamber. It is mandatory to mount the electric water pump.
Particularly the internal geometry of the crankcase designed to have more space reserved for the transmission unit. The goal is to use a new transmission belt with larger dimensions in height and width in order to transmit the maximum of
motor skills. The gear casing allows mounting on bearings of the intermediate shaft and the wheel shaft while the outer casing cover remains the original.
