GRAND-SPORT has marketed their own racing piston since 2004, and no piston product has influenced the Vespa scene like theirs. GRAND-SPORT aka GS-Pistons earnt recognition over the years and has driven home countless successes in all VESPA race series. When it comes to cast iron cylinders and power, most only want GRAND-SPORT piston products.
High quality metal alloys with at least 18% silicon. Furthermore, GRAND-SPORT pistons are equipped with high quality pistons rings made of ductile cast iron with chromed race and 1mm thick ring. A further plus: lighter biconical gudgeon pins.
Conclusion: if high quality materials, well thought out technical details and dependability are what you're looking for, this is it. GRAND-SPORT pistons are a byword for powerful and durable cast iron cylinders.
Aluminum/ ø 55.00/ 55.50/ 56.00mm/ 1mm piston ring
High quality metal alloys with at least 18% silicium, 29mm compression height, pin distance suitable for all VESPA PV/PK 125 original cylinders. 1mm piston ring made of ductile cast iron with chromed race, biconical gudgeon pins.
Before installation, control piston play and piston ring stop play; adjust if necessary!
As a rule, to get optimal performance, compression/pinch slot should be modified; upper cylinder modified/milled (compression height original piston 36,5mm)
SIP-TIP: Main jet adjustment and new spark plugs are a must. Ideal for original cylinders would be an adapted and much more stable MALOSSI cylinder head! Casing should be modified to fit new transfer size.