Made in GermanyComplete sports clutch incl. primary wheel and reinforced repair kit for Vespa Wideframe models from 1954 onwards (VN1T (60001-), VN2T, VL1T, VL2T, VL3T, VB1T, ACMA (56-58)
The SC clutch is based on the well-engineered and proven BGM Superstrong clutch for PX models. It therefore offers modern and stable clutch technology for 125-150cc Vespa wideframe engines from 1954 onwards.
These already have a clutch cover whose three fastening screws are located outside the outer radius of the cover. This corresponds to the modern standard of Vespa PX models. The older models built before 1954 (e.g. VM1T/VM2T) still have internal screw connections. These do not fit large clutch types such as the one shown here with Øa=115 mm. We offer a separate type of coupling here.
The major advantages of converting to the SC coupling:
FITTING
The SC clutch replaces the conventional clutch type used in Vespa from approx. 1954 onwards and can therefore be used in Vespa 125, VN1T (60001-), VN2T, Vespa 150 VL1T, VL2T, VL3T, VB1T, ACMA 150 GL (1956-1958).
MODIFICATIONS
As the clutch has a larger diameter, minor modifications to the engine housing and clutch cover are required for installation. For this purpose, material is removed from the drip nose (for the transmission oil) positioned at 12 o'clock in the engine housing as well as in the clutch cover. Also ensure that there is sufficient clearance on the flat surface at the 9 o'clock position and remove some material here if necessary. The set includes a spacer and seal. These ensure a greater distance between the clutch cover and the clutch in order to compensate for the increased height of the clutch.
TRANSMISSIONS
More powerful engines require longer gear ratios in order to make optimum use of their potential, otherwise the engine will literally rev to nothing. The Vespa wideframe models all have a primary reduction ratio of 22/67 (clutch-primary gear) ex works.
'Engine halves remain too variant'
The easiest way to install a better clutch and at the same time a longer gear ratio is to use our SC6723L clutch. This uses a clutch pinion with one more tooth (23T instead of 22T) and can be used with the original primary wheel (67T). This alone increases the top speed by approx. 5 km/h. Ideal for light tuning or standard engines that are driven with a high-torque exhaust system.
'Engine halves must be of the same variant'
Engines that have been significantly increased in performance (e.g. tuning cylinders, exhaust and carburetor) require a longer gear ratio than the plug&play 23/67Z ratio. To do this, not only the clutch pinion is changed, but also the large primary gear in the engine. This requires the engine to be completely dismantled. However, this work is worthwhile and does not require any more work during a revision.
Wideframe engines from around 1954 onwards have the more modern design of the primary drive, easily recognizable by the cover plates, which are fastened with 6 rivets. These primary drives can be fitted with primary wheels from bgm Pro and Bollag Motos and reinforced bgm primary repair kits.
Diagonal or straight?
The bgm Pro primary gears for the Wideframe are always straight-toothed. They offer the advantage that they do not exert any axial (lateral) forces on the crankshaft and the auxiliary shaft. This effectively prevents the risk of premature wear of the crankshaft bearing seats due to wandering bearings. The straight-toothed bgm Pro transmission parts are also manufactured with such high precision that they run just as quietly as the original helical-toothed parts.
In general, longer ratios can be realized with the bgm Pro primary gears (62Z/63Z) than with the helical gears from Bollag Motos (64Z/65Z). As long as you stick to one type of gearing (helical or straight), all sprocket/primary wheel combinations on offer are compatible with each other (a 23T clutch can be used on the 62T or 63T primary wheel, or a clutch can be converted from 22T to 24T without having to change the primary wheel).
Unlike most PX and Smallframe models, the Wideframe engines do not always use the same secondary gearbox, but depending on the engine type there are different 3-speed and 4-speed gearboxes which always consist of the same primary reduction of 22 teeth on the clutch pinion and 67 teeth on the primary wheel.
Many engine types can be converted from a 3-speed gearbox to a 4-speed gearbox. It is therefore necessary to select the new primary drive to match the gearbox used. We have based our selection on everyday experience. A Rally 200 serves as a reference. This delivers approx. 9-10 hp on the road and runs at approx. 100 km/h at 6,000 rpm.
The following primary reduction ratios are based on this performance, as the engines of the Wideframe deliver similar power and torque values to the rear wheel due to the power increase. With the original tire size (3.50 x 8") of the respective models, the following gear ratios result for performance-enhanced vehicles:
VL, VB (3-speed, 14-56, 20-49, 27-42)
(optionally also 23 / 65 helical teeth)
GS 150 VS1-5 No changes to the primary are currently possible here due to the design of the clutch.
4-speed ACMA GL and replica (Pinasco) (13-57, 18-52, 23-47, 27.43)
(optionally also 24 / 65 with helical teeth)
4-speed BGM Sport on 3.50-8" (12-57, 13-42, 16-38, 19-35)
(US18419)
DE | €
