Sadly, all producers – PIAGGIO included – of the COSA II clutch baskets, cannot guarantee the usual high quality production standards. Their inclusion in even the more moderate tuning projects often resulted in the mechanical disaster scenario of an exploded clutch, with sheared rivets and shabby tolerances also not being unusual. The clutch could only become effective in tuned motors with the inclusion of an aftermarket race or sport clutch basket. All of these horror stories did not do the reputation of the PIAGGIO COSA II clutch any good at all.
SIP has had the COSA II clutch basket put back into production. Brand new press moulds were designed for both the production of the inner and outer profiles of the new clutch basket. The basket is constructed of a high quality steel, the flanks then induction hardened and precision finished. The groove that holds the clutch cluster circlip has been optimized for a tighter fit, the interior has been designed to enable the use of 16 clutch springs and is more effectively fixed together using rivets specially produced for this clutch. The cast alloy baseplate also fits in all other COSA II clutch basket versions. The clutch cover does not have to be modified and the use of a gasket surface area spacer is also unnecessary. 'Plug and play' is the name of the game here.
We also have the original PIAGGIO COSA II clutch available in its original form. A version is also in stock with the SIP interior modified for use with 16 springs. We recommend a reinforcement ring to be fixed around the outer diameter of this clutch basket in its original form if it is intended for use in the more powerful motor setups.
Conclusion: The SIP basket conversion solves all the existing problems experienced with the original PIAGGIO COSA II clutch, so helping restore it to former glory.
SIP-TIP: The strengthened clutch cluster circlip produced by SURFLEX or SIP is a must! Do not forget to order a new clutch holding nut, safety washer, thrust plate and a pushrod. New clutch friction plates are also recommended when doing this job. Clutch holding and removal tools also make this job a lot easier.