“PIAGGIO has revolutionized the world of large frame engine transmissions with the introduction of the COSA 2 clutch. All existing large frame friction issues have been resolved. Since 1995 the COSA 2 clutch has been used in all VESPA PX EFL / ’98 / MY / ’11 and of course the COSA 2 models built by PIAGGIO. Comes complete with 4 friction discs, 8 springs and a sturdy clutch basket design. Due to the increased pressure created by the increased number of springs and the increased friction surface, power can be transmitted more effectively between the crankshaft and gearbox. Precision laser cut clutch plates avoid any problems with clutch engagement. No jerking, no slipping, an optimal release point and all this in combination with a light and easy action of the clutch lever, even when using a stronger spring set. In the past, there were huge fluctuations in the quality of NEWFREN and PIAGGIO parts. This is why we recommend that all Largeframe riders with more than 15PS use the SIP clutch. This SIP COSA 2 Standard / Sport clutch is equipped with the SIP clutch basket specially made for this purpose: induction hardened, precise notch, reinforced circlip. The interior of the clutch basket, designed and manufactured exclusively for SIP, has 16 clutch spring recesses so you can use the 8 or 16 COSA 2 clutch assembly springs, one-piece outer ring etc. This clutch will not slip, is plug & play ready and works exactly as originally intended. Features SIP standard clutch: – Up to 15 PS – Induction hardened basket with precise notch – reinforced circlip – inner part forged and riveted 16 times – equipped with 8/16 spring – spring rate: L, 8 springs used – Plug SIP Sport Clutch features: – up to 25 PS – Induction hardened basket with precise notch – reinforced circlip – inner part forged and riveted 16 times – equipped with 8/16 spring – spring rate: L, 8 springs used – Plug The clutch basket of the SIP COSA 2 Race clutch is CNC machined from a solid block of aluminum alloy and is hardened using a nitration process for increased durability. The circlip groove has been optimized, i holes and notches reduce weight. The interior of the clutch basket, designed and manufactured exclusively for SIP, has 16 clutch spring recesses so that the 8 or 16 springs of the COSA 2 clutch assembly can be used. The rivets were made specifically for this unit, with grooves for easy assembly and anti-corrosive treatment. Because of this we can keep this item at a low price, coupled with the use of the highest quality materials. SIP Race Clutch features: – up to 25 PS – CNC machined basket with precise carving – low weight through cutouts – inner part forged and riveted 16 times – equipped with 8/16 spring – spring rate: L, 8 springs used – Break through the necessary clutch cover The overall design of the SIP “Ultrastrong” clutch basket is based on that of the MMW “Superstrong” type and is also built for SIP by MMW. Until now this type of clutch was only suitable for dedicated racing use, but now, thanks to a slimmer design, it can also be considered as part of a set of street engines. The SIP version of the ‘Superstrong’ clutch also does without the standard COSA 2 clutch baseplate, which has been replaced by a wave-shaped baseplate. There are no rivets that can be cut in its construction and ten COSA 2 clutch springs are installed. With regards to the materials and manufacturing quality of these clutch bushings produced by MMW, these items represent absolutely cutting-edge engine components. In contrast to the original items, these are machine pressed directly onto the base plate of the clutch assembly and thus reduce clutch grip or vibration. The main difference between versions of the MMW “Superstrong” clutch lies in the design of the clutch basket. The holes found on the sides of the basket of the MMW versions are absent on the SIP type. The SIP clutch basket is also constructed using a more easily modifiable EC80 type steel, which is better known as F1 steel in Italy, unlike the MMW clutch basket which relies on a 42CroMo4 material for its manufacture. Our SIP clutch basket was designed to fit more easily under the original clutch cover, with minimal modification required. Some clutch covers/wraps only require one pair of internal drip ridges to be carefully removed using a regular set of pliers! This type of clutch basket has already been successfully proven in many engines capable of producing up to 30 PS and even more. We have decided to call it a “sports” clutch basket and not a “race” type because it is compatible for inclusion in your engine set-up with minimal crankcase modification necessary. SIP Ultrastrong Clutch features: – up to 25 PS – basket incl. internal part CNC machined with precise carving – spring rate: L, 10 springs used – Plug Attention: not compatible with pinasco clutch bush no. 59366000! SIP-TIP: Don’t forget to order the new push plate, push rod, lock washer and nut. Be sure to dip the clutch plates back into the gear oil. Possible gear ratios: Clutch sprocket STD helical teeth STD helical teeth STD helical teeth straight teeth DRT straight teeth 67 68 65 64 62 20 3.35 3.40 helical teeth 21 3.19 3.24 3.10 helical teeth 22 3.05 3.09 2.95 helical teeth 23 2.83 helical teeth 22 2.91 straight teeth 23 2.78 straight teeth 23 2.70 straight teeth 24 2.58 straight teeth 25 2.48 straight teeth”