Up for sale is TEAM 1991 Formula Mach I XTC SS SR Ski-Doo PRIMARY SPRING SKI-DOO BLACK/PURPLE/PINK. The vendor part number is 210141-017. Please read the title to know what is for sale Venom primary springs are made from high tensile silicon wire to maintain rate over many cycles. Primary springs control engagement and shift RPM. Fine tune your primary clutch with Venom springs manufactured from high tensile wire to exacting tolerances.