Slot-controlled, fan-cooled 38 mm (50 ccm) tuned cylinder compatible with Swiss Sachs 50/2 and 502 engines, which were installed in Alpa, Caravelle, Comet, DKW, Eiger, Göricke, Hercules, Prior, Pony Junior, Rico, Rixe, and Walco mopeds.
Chrigi from Gfellers-Zweirad was personally involved in the development of the “Wummer” racing cylinder and tested it extensively. His feedback was directly incorporated into the design. The result is a cylinder that delivers impressive performance, particularly in the mid-range. The focus here is not on peak power, but on smooth, strong power delivery.
The M40x1.5 mm exhaust thread allows for the installation of all standard exhaust systems. Thanks to the stock-style 37x37 mm bolt pattern for the cylinder head, all standard heads can also be mounted here.
The cylinder is camouflaged with the “30 km” lettering.
Notes:
The cylinder is shipped unassembled and without a piston, gasket set, studs, or other components.
The 60x40 mm bolt pattern for the cylinder studs is designed for Swiss engines and is therefore not suitable for German models.
For optimal power output and a precise fit, the cylinder should be used with a 17 mm swiing® tuning carburetor. This should be installed with a short air filter cap, a matching clamp (short), and the corresponding cover plate (long/deep).
You can find all the optional products listed here in the accessories section.
A good, affordable standard replacement part. GPO – GOOD PARTS ONLY.
| Manufacturer | GPO |
| Displacement | 50 ccm |
| Crankshaft stroke | 42 mm |
| Material | Gray cast iron |
| Nominal diameter | 38 mm |
| Ø cylinder neck | 44.8 mm |
| Ø Outlet outside | 40 mm |
| Camouflaged | Yes |
| Number of fixing points | 4 pcs |
| Hole spacing inlet | 32 mm |
| Outlet type | Union nut |
| Sachs | 502 (Saxonette) - AL , AML 50/2 - L CH (0.8 PS) , ML CH (0.8 PS) , MB (2.6 PS) , MLB (2.6 PS) |
Accessories & related products
GPO piston 38 mm | Sachs 50/2, 50/3, 50/4 fan-cooled
Nominal diameter: 38 mm · Manufacturer: GPO · Ø outside piston (A): 37.94 mm · Compression height (C): 27.5 mm · Curvature (D): 3.5 mm · Total piston height (E): 53 mm · Number of piston rings (F): 2 pcs · Piston ring mold: Rectangular ring · Piston ring impact: Flank safety device (FS) · Ø piston pin (B): 12 mm · Piston ring height: 1.7 mm · Thick piston ring: 2 mm · Weight piston kit: 78 g · Alternative version of the Sachs OEM number: 0290 058 025
EUR 40.20
swiing® revival carburetor 17 mm Bing SSB 1/17/69
Manufacturer: swiing® revival parts · Camouflaged: No · Component group Carburetor: Carburetor complete · Material: Aluminum · Carburetor type: SSB · Nominal diameter: 17 mm · Hole spacing inlet: 31 mm · Ø fuel hose connection: 6 mm · Mixed oil connection: No · Vacuum connection: No · Choke control: without choke · Nozzle size: 76 · Mounting type: Flange · Total length: 132 mm · Width: 85 mm · Height: 100 mm · Area of application: Standard · Area of application: Tuning
EUR 150.60
swiing® revival stud bolt set M5x26 inlet (10.9 strength) | Sachs 50/2, 502, 50/3
Width across flats: 8 mm · Manufacturer: swiing® revival parts · Material: Steel · Surface: galvanized (blue) · Thread type: M5x0.8 (standard thread) · Drive: External hexagon · Nominal diameter (thread): 5 mm · Thread length: 7 mm · Strength class: 8 · Strength class: 10.9 · Thread length: 14 mm · Total length: 26 mm
EUR 6.75
swiing® revival exhaust manifold 28 mm chrome | Sachs 50/2, 50/3
Manufacturer: swiing® revival parts · Material: Steel · Surface: chrome-plated · Color: Chrome · Ø outside: 28 mm · Ø External connection: 32.25 mm · Ø inside: 25.7 mm · Mounting type: Union nut · Total length: 368 mm · Sachs OEM no.: P5005
EUR 53.30
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GPO piston 38 mm | Sachs 50/2, 50/3, 50/4 fan-cooled
Nominal diameter: 38 mm · Manufacturer: GPO · Ø outside piston (A): 37.94 mm · Compression height (C): 27.5 mm · Curvature (D): 3.5 mm · Total piston height (E): 53 mm · Number of piston rings (F): 2 pcs · Piston ring mold: Rectangular ring · Piston ring impact: Flank safety device (FS) · Ø piston pin (B): 12 mm · Piston ring height: 1.7 mm · Thick piston ring: 2 mm · Weight piston kit: 78 g · Alternative version of the Sachs OEM number: 0290 058 025
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swiing® revival stud bolt set M5x26 inlet (10.9 strength) | Sachs 50/2, 502, 50/3
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