German specialist SIP Scootershop has developed an all-new high-tech clutch for Vespa Largeframe models - a "Supersport" version of the unbeaten BFA clutch.
CEO Ralf Jodl explains that "with this clutch, the operating principle of the Vespa Largeframe clutch has been reversed. This is to connect less mass rigidly to the crankshaft and has the effect of improving operability. Together with four discs and nine springs, this is an almost indestructible clutch that is perfect for any application.
"The whole thing fits under the original clutch cover of the PX and creates low mass on the crankshaft - with 4 clutch plates and a version available with a toothed flange.
"The principle of the inverted Vespa Largeframe clutch is becoming increasingly popular - the grinding-in and separation behaviour are convincing. Unfortunately, these clutches are usually expensive, which increases the hurdle for the conversion. The aim of the "Supersport" clutch is to improve the ease of use, even on 20-30 hp engines.
"The small company BFA from Italy made a start and was the first to reverse the operating principle of the clutch for Vespa Largeframe models. This means that the outer basket no longer rotates with the crankshaft, but the inner basket.
"This principle was copied by several manufacturers, but the performance potential of the BFA clutch was never fully realised. SIP bought the clutch from BFA in 2019 and continues to have it produced by the same manufacturers in Italy.
"The clutch works perfectly and can withstand power of over 70 hp without any problem. As the full performance of the BFA clutch is rarely needed, we decided to develop a similar clutch with 4 discs. The aim was to transfer the perfect function and durability of the BFA clutch into a cheaper clutch that can easily transfer 50 hp.
"The result is impressive and can only be matched or surpassed in function and durability by the five-disc BFA clutch. As with the BFA version, the pinion is bolted on with 12 screws. The four clutch plates are taken from the design of the Cosa clutch, SIP pads on aluminium sheets are used.
"This has made it possible to increase the number of plates, both on the inside and on the outside basket, which increases the service life of the lining and separating discs. Nine springs provide sufficient contact pressure. CNC-manufactured individual parts made of high-quality aluminium ensure low weight and high-quality standards. The pressure plate is mounted on ball bearings and the pads can be changed while the clutch is installed.
The "Supersport" clutch is available in different versions - suitable for the original clutch flange of the PX crankshafts or with toothing that forms an almost indestructible connection with the crankshaft.
"However, this requires the use of a crankshaft with the same toothing. The toothing was first found on the crankshaft of the BFA 306 engines, but we now also offer it for a whole range of crankshafts for standard PX engine cases.
"If you want to combine the SIP 'Supersport' clutch with a large primary gear Z64 from, for example, Polini, Malossi, BFA or other manufacturers, you can buy the clutches 'without gear' (93440000 and 93441000) and combine it with one of the BFA gears (87482600, 87482700, 87482800).
"The splined crankshaft stub cannot be combined with separate lubrication. The reason is that there is no washer clutch with splines and inner diameter for M14. The version for the original flange can be used with separate lubrication.
"However, the protruding M5 countersunk screws may rub against the axle of the oil pump gear in the engine casing. To remedy this, it is sufficient to grind the axle of the oil pump approx. 0.5 mm lower. Alternatively, the protrusions of the screws can be ground off.
"The 'Supersport' clutch for the Vespa Largeframe models is the absolute high-end solution for a clean, reliable and easy-to-use power connection between engine and gearbox," concludes Ralf.
Features include a CNC milled aluminium outside basket, 12-pinion bolted with primary pinion, CNC milled steel inside basket, 4 full 'Cosa' type pads, bearing mounted pressure plate, CNC milled aluminium cover plate top and bottom and nine springs. Clutch plates can be changed in installed condition and can be mounted with the original PX 200 clutch cover.
SIP SCOOTERSHOP GMBH
