The Italian crankshaft forge Tameni has redesigned the crankshaft of the Vespa GS150 models and improved it in detail. The precisely machined shaft has a needle bearing at the upper end of the connecting rod, just like the last version of the GS150 models, the VS5. This significantly improves the durability of the shaft and meets modern standards. Nevertheless, the oil content of the two-stroke mixture should not be reduced too much as the lower connecting rod eye is not located in the cooling and lubricating inlet gas flow as in the later rotary vane engines.
The shaft also fits into the engines of the VS2, VS3, and VS4 models. Thus, these engines are significantly upgraded and can also be driven with continuous full throttle without any problems.