What honey is for the APE, Italian for bee, a POLINI is for the engine.
In direct comparison with the DR, the POLINI scores points with a substantially longer exhaust port timing and the 6 transfer ports. Revs and power go hand in hand with the POLINI, but it is already crying out for a longer primary transmission. Anyone who provides the cylinder with the appropriate periphery will be rewarded with a solid basis for 2-person operation. Longer distances and full-throttle stretches will then also be no problem!
Conclusion: Powerful cylinder, layout strongly resembles that of the 75ccm POLINI, but has clear advantage in capacity. Sportier than the competition, thanks to the higher compression and the additional transfers. With the right primary, thermally balanced and long-lasting.
Cast iron/ 50mm bore/ 6 transfer ports/ 84.43cc
Cast iron cylinder, stroke 43mm, 6 transfer ports, pistons with 2 piston rings, exhaust with a width of 27.5mm (chord dimension), 6mm exhaust studs, original POLINI cylinder head is included in delivery, compression 11:1, incl. gasket set. Jets should be adjusted.
Fits all Vespa 50/PK/XL/XL2 models, except PK automatic. Transfer match the originals, casing must not be modified.
SIP-TiP: Adjust the main jet and install new spark plug, of course. It is here a must to change the transmission, min. a 3.72 primary, max. 3,00. The engine can be made even sportier with a 16/ 16 carburettor, original exhaust with a wude manifold or the SITO banana.
Alex, SIP-Team, 05/2009:
“The cylinder has loads of power. Our SIP 50ccm Ape simply pulled 1.5 tons of catalogues and 3 SIP men in the cab (against tipping);-)“