Ø 68,5mm
aluminium

Ready for take off! GRAND-SPORT are, since the turn of the millennium, the most innovative workshop when it comes to the development of performance pistons for classic models of Vespa!

Their very successful range of Vespa pistons have been in existence for over a decade and have received enlargement in the form of GRAND-SPORT's very own piston for the 208 / 210cc race cylinders produced by POLINI! These performance pistons possess an optimised overall construction, matched and enlarged piston side ports and a CNC machined boost port window. A lighter biconically shaped gudgeon pin is also included in the conversion kit. The 18% proportion of silica in the casting material of the piston ensures its greater durability and also protects against heat-seizures occurring. The piston itself is, of course, cast in 'Bella Italia' and the famous 'bulletproof' GRAND-SPORT piston rings are also provided as the icing on the cake for this quality product! Say goodbye to fragile 'L' rings and possible breakage! The compression height is identical to that found on the original POLINI piston and so is a 'Plug and Play' replacement. The piston rings are situated a little lower on the skirt of the piston to enable simple long-stroke crankshaft conversions.

Conclusion : All in all a well rounded piston conversion kit that leaves no reason for desire.

Aluminium / 68.00 / 68.50 / 69.00 mm diameters / 2 x 1.0 mm STEEL piston rings

Aluminium piston, minimum of 18 % proportion of silica, 42.5 mm compression height (identical to POLINI original), inner ribbed structure and a reinforced gudgeon pin opening or increased stability, CNC machined boost-port window which has also been enlarged and repositioned, bridged and enlarged piston side ports, 2 x 1mm STEEL piston rings with chromed cylinder contact surfaces. Please note : Further information, product details and important mounting tips can be found on the right hand side under 'Article download'. Recommended piston play clearance for cast iron cylinders : 12/100 – 13/100mm, for aluminium cylinders : 8/100 – 9/100. Always check the piston play and piston ring clearances before final assembly!

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