BGM Pro special crankshaft 43/87 mm with Ø25 mm stub for Vespa Smallframe
BGM Pro special crankshaft with the stroke and connecting rod of the 50cc models (43 mm/87 mm) combined with the large alternator stub (Ø24/25 mm) of the PK125 ETS models.
Most stable 50cc crankshaft on the market, fits into any smallframe housing with the corresponding bearing: V50, PK S, PK XL, PK XL2! See accessories for conversion bearings.
Suitable for the following engines in order to be able to use cylinders for V50/PK50 (50-112cc):
- Engine case LML SE125 (as replacement for PK50XL2)
- Motovespa PK75 XL (96M/104M) and PK75 FL (127M/128M)
- Vespa PK125 ETS engines
- Generally all Vespa Smallframe V50, PV125, ET3 engines, if they are fitted with a conversion bearing (25x47x12mm) for the alternator side.
VESPA PK50 XL2
The BGM Pro crankshaft uses the large stub of the ETS models with Ø24/25 mm so that the LML SE125 engine cases we offer can also be used with the small cylinder of the 50cc class. It is now possible to use the LML SE125 engine cases as a replacement for defective Vespa PK50XL2 engine cases.
MOTOVESPA PK75 XL/FL
The engines of the Motovespa PK75XL and FL models have a cylinder with Ø47mm bore and 43 mm stroke ex works. As a special feature, Motovespa uses a long 97 mm connecting rod with a 15 mm piston pin (like the original 125cc models). This means that none of the commercially available tuning cylinders can be used on these engines. The stroke is too small for 125cc cylinders and the connecting rod is too long and the connecting rod eye too large for cylinders in the 50cc class. The BGM Pro crankshaft closes this gap and allows the use of all 50cc cylinders on MOTOVESPA PK75 XL/FL engines, suitable for V50/PK50 (50-112 cc).
TECHNICAL DATA
- Stroke: 43 mm
- Connecting rod length: 87 mm
- Connecting rod eye: Ø17mm (suitable for Ø12mm piston pin)
- Diameter bearing seat alternator: Ø25mm
- Diameter of alternator shaft seal seat: Ø24mm
VESPA PK125 XL2/ETS
The engine of the Vespa PK125 XL2 and ETS models also has the large alternator stub diameter (Ø24/25 mm) ex works. They can therefore also be used with the BGM crankshaft for cylinders in the 50cc class.
VESPA SMALLFRAME V50, PV125, ET3
The engine cases of all smallframes with 50-125cc (except automatic) can also use this crankshaft if a bearing with the dimensions 25x47x12mm (6005 C3 or NU1005) is used instead of the normally used 6204 (20x47x14mm) ball bearing on the alternator side.
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