Extremely durable—even for very powerful engines
The Stingworks Sei Giorni GP is a heavy-duty clutch designed for classic Vespa Wideframe and early Largeframe engines. Its design is suitable for everything from stock engines to very high-performance touring and racing setups.
The reinforced hub features significantly more material in the critical area around the crescent-shaped groove. At the same time, the 12 tabs on the friction plates distribute torque over a wide area within the clutch basket. This reduces localized stress and counteracts the typical buckling of the basket sides.
High power transmission with low operating force
The modern 6-disc lining package offers a particularly large effective friction surface. As a result, comparatively low spring forces are sufficient to reliably transmit even high engine torque.
With the included 8 BGM PRO XL springs, the clutch remains smooth and easy to modulate—a true two-finger clutch. At the same time, it accommodates setups with over 30 PS or more than 25 Nm.
Plug-and-play on the engine and freely adjustable
Installation requires no modification to the engine case or stock clutch cover. The set is supplied for self-installation and intentionally does not include a clutch pinion.
For proper assembly, the supplied retaining ring for the clutch basket should be shortened by about 5 mm before installation. This minor adjustment can be easily made with a side-cutting plier. Afterward, check to ensure that the retaining ring sits completely and without tension in its groove.
Standard Cosa2-type clutch pinions are used. The number of teeth and tooth profile must match the existing primary sprocket. This allows the gear ratio to be specifically tailored to engine power, transmission, tire size, and intended use.
Original Stingworks
Made in Germany
Plug-and-play on the engine
Two-Finger Clutch
6 friction plates
Over 30 PS / 25 Nm
19-mm lining package
without clutch pinion
Shorten the retaining ring by approx. 5 mm
Important Installation Note Regarding the Retaining Ring
The retaining ring for the clutch basket included in the set should be shortened by about 5 mm before installation to ensure proper fit.
Shorten the retaining ring by approx. 5 mm before installation
You can easily trim it with a side-cutting pliers
Then check the cut end for any protruding or sharp edges
Insert the ring neatly into the designated groove
Check for a secure fit around the entire circumference
The retaining ring must not be skewed or jammed outside the groove
This adjustment applies exclusively to the retaining ring. No machining of the motor housing or the clutch cover is required.
Key Benefits
Genuine Stingworks: developed and manufactured in Germany
Extremely durable: for stock and high-performance engines
Plug-and-play on the engine: no modification of the engine case or clutch cover required
Two-Finger Clutch: low operating force despite high torque capacity
Reinforced hub: more material around the crescent-shaped groove
12 friction plate tabs: wide-area power transmission and reduced load on the clutch basket
19-mm friction plate pack: compatible with the flat clutch housing of earlier engines
Free gear ratio selection: can be combined with compatible Cosa2 clutch pinions
Easy Retaining Ring Adjustment: The retaining ring can be shortened with side cutters
Original Stingworks quality
The Sei Giorni GP is developed and manufactured in Germany. The precision-engineered clutch basket, reinforced hub, and modern BGM PRO friction plate package form a robust unit for reliable street, touring, and racing engines.
The 12 tabs on each friction disc distribute the forces across more contact surfaces than conventional friction plates. As a result, the basket flanks are subjected to less localized stress and maintain their dimensions longer, even under high torque.
Technical Specifications
| Version |
Installation kit for self-installation |
| Friction Discs |
6 pieces featuring modern KTM friction technology |
| Lining tabs |
12 per friction disc |
| Steel discs |
2 x 1.0 mm and 4 x 1.5 mm |
| Springs |
8x BGM PRO XL, 6.5 N/mm |
| Load capacity |
over 30 PS / 25 Nm |
| Pad stack height |
19 mm absolute |
| Overall height |
45.6 mm with the clutch properly assembled |
| Clutch pinion |
Not included |
| Pinion type |
Cosa2 |
| Retaining ring |
Included in the package; trim approx. 5 mm before installation |
| Tool for shortening |
Standard side-cutting pliers |
| Modifications to the motor |
No modifications to the motor housing or clutch cover are required |
Free choice of gear ratio
The clutch pinion is intentionally not included in the set. This allows the primary gear ratio to be selected to match the specific engine.
Note on the clutch pinion
A Cosa2-type clutch pinion, available separately, is required
The number of teeth and tooth profile must match the installed primary sprocket
Straight-toothed and helical-toothed components must not be combined
Check the primary sprocket and desired gear ratio before ordering
Compatible Vehicles
This version is designed for Vespa Wideframe and early Largeframe models with a flat clutch mount.
| Vespa Wideframe |
VM, VN, VL, and VB, model years approx. 1953–1959 |
| Early Vespa Largeframe |
VNA, VBA, VNB, VGLA, and VBB1T |
| Motovespa 125S |
V72M, V58MS, and V60MS |
| Motovespa 125N |
V56M, V58M, V60M, and V101M |
The vehicle designation and the engine’s flat clutch mounting are decisive factors. For licensed builds and modified engines, the clutch mounting and primary drive must be checked before installation.
Scope of Delivery
1x original Stingworks Sei Giorni GP clutch basket, including reinforced hub
1x BGM PRO 6-disc friction pack
2x BGM PRO steel clutch plates, 1.0 mm
4x BGM PRO steel clutch plates, 1.5 mm
8x BGM PRO XL clutch springs
1x brass clutch thrust washer
1x Retaining ring for the clutch basket – trim approx. 5 mm before installation
The clutch pinion is not included.
Note on the 19-mm version
The assembled set of friction and steel plates has a total height of 19 mm. This positions the clutch basket further toward the interior of the engine and requires less installation space on the side of the clutch cover.
This version is therefore intended for the shallow clutch housing of the listed Wideframe and early Largeframe engines. The later Largeframe and PX versions, on the other hand, use a 17-mm-high friction plate stack.
The clutch basket and hub are identical in both versions. Only the lining pack height—and thus the axial position of the clutch basket—differs.
Installation Instructions
The set is shipped unassembled
Install the friction and steel discs in the specified order
The fully assembled friction plate stack must have an absolute overall height of 19 mm
Use a compatible Cosa2 sprocket that matches the existing primary sprocket
Trim the retaining ring by approximately 5 mm before installation
Standard side-cutting pliers can be used for trimming
After shortening, insert the retaining ring completely into the designated groove
Check that the retaining ring fits correctly and without tension around its entire circumference
Check the friction plate stack height, separation travel, and axial play
Ensure there is no contact between the clutch and the clutch cover
Coat new friction discs with suitable transmission oil before installation
Adjust the retaining ring before installation
Before final installation, the retaining ring should be shortened by approximately 5 mm. This allows it to be positioned correctly in the groove of the clutch basket.
Required shortening: approximately 5 mm
Suitable tool: side-cutting pliers
Do not excessively widen or bend the ring after trimming
Check the cut edge for sharp edges or protruding areas
After installation, check that the ring is fully seated in the groove
Do not install the coupling until the retaining ring is correctly and securely seated
FAQ
With the included spring set, the Stingworks Sei Giorni GP is suitable for setups with over 30 PS or more than 25 Nm. For high-performance engines, the spring set can be further reinforced.
The 6 friction plates provide a large effective friction surface. This allows high torque to be transmitted even with comparatively low spring force. This reduces the amount of hand force required on the clutch lever.
No. With the correct vehicle application and proper installation, the clutch can be used without modifying the engine housing or the stock clutch cover. Only the supplied retaining ring should be shortened by about 5 mm to ensure a proper fit.
No. This version is supplied as a complete installation kit for self-installation.
No. A Cosa2-type clutch pinion, available separately, is required. The number of teeth and tooth profile must match the installed primary sprocket.
The 19-mm-high lining pack positions the clutch basket further toward the inside of the engine. As a result, the clutch requires less installation space on the clutch cover side and fits the flat clutch mounting surface of the listed engines.
The clutch basket and hub are identical in both versions. The different lining pack heights position the clutch basket to fit the respective clutch mounting. This 19-mm version is designed for Wideframe and early Largeframe engines with a flat clutch mounting.
It is designed for compatible Motovespa 125S and 125N engines. Since variations are possible depending on the model year, engine version, or modifications, the clutch mounting and primary drive must be checked before installation.
Yes. To ensure a proper fit, the retaining ring should be shortened by approximately 5 mm before installation. This can be done easily with a pair of side cutters. After insertion, check that the ring sits completely and without tension in its groove.
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