Description
Racing HPC crankshaft Stage6 HPC 44mm stroke Derbi D50B0
High-quality tuning parts from Stage6: Crankshaft Stage6 HPC 44mm stroke / 90mm connecting rod Derbi Euro 3 / Euro 4, the perfect crankshaft for racing and high-end cylinders.
Design and advantages of Stage6 HPC crankshaft
Tuning specialist Stage6 developed this High Primary Compression (HPC) crankshaft especially for tuned racing and heavily tuned high-end racing engines.
The high-precision full-circle crankshaft has been optimized through targeted material reduction on the shoulder side, allowing it to achieve excellent balancing in combination with the lightweight metal counterweights used. The connecting rod, specifically designed for this crankshaft, features a width of 14 mm (instead of 12 mm), significantly increasing its strength. This reduces bearing wear while ensuring enhanced stability, even at extremely high rotational speeds.
Use of the Stage6 long-stroke crankshaft HPC
This HPC crankshaft was built for more heavily tuned engines and offers the possibility of significantly increasing the displacement of a 70cc or 80cc engine by adding a cylinder spacer and reworking the cylinder. For optimum performance we recommend the Top Peformances 86cc cast iron Derbi cylinder.
For optimum installation, we recommend the use of a new crankshaft bearing set, new engine gaskets and Stage6 gear oil. You can find all these parts at the bottom of the page.
Note:
- The crankcase must be machined in the area of the connecting rod so that it runs freely. We recommend dry fitting so you can clearly see the connecting rod.
Technical data racing crankshaft HPC from Stage6
- Connecting rod: 90mm (original)
- Stroke: 44mm
- Piston pin: 12mm (original)
- Small end bearing: 12x17x15mm
- Balance factor: 54%
- Maximum speed: 16,000 rpm
- Use: Racing / High End Racing
- Derbi Euro 3 / Euro 4 (Derbi, Aprilia, Gilera from 2006)
Stage6 HPC
The HPC crankshafts from Stage6 are the brand's racing crankshafts. There are versions with standard stroke and with long stroke, the HPC shafts are available for both 50cc motorcycles and scooters.
HPC crankshaft performance
The HPC crankshaft (HPC for High Primary Compression) is very robust and also suitable for high RPMs, e.g. in combination with the Stage6 Big Racing cylinder.
- Made entirely of metal (no plastic inserts)
- Precise balancing
- Forged connecting rod
- Suitable for sport to racing setups
Supplied without crankshaft bearings. Please also remember to get the necessary tools, e.g. a flywheel puller.
How to change a crankshaft?
The crankshaft is one of the main components of the engine and is responsible for the smooth operation of motorcycle, scooter and moped, whether with two-stroke or four-stroke engine. The longevity of the engine depends not only on the proper condition of the crankshaft, but also on the fact that it is properly mounted.
For a correct installation of the crankshaft, we recommend our tutorial: Crankshaft disassembly and assembly.
How can I tell if my crankshaft is Damaged?
A broken crankshaft causes metallic noises, unusual vibrations, leaking oil seals and drastically reduces the performance of the two-wheeler. In any case, the vehicle must be stopped immediately to prevent the damage from getting worse.
Please note that whenever the crankshaft is changed and serviced, you'll have to install new crankshaft bearings.

Tuning Level: High End racing
We categorize our products into different performance levels Original, Sport, Racing and High End , so that our customers can choose the right parts for their setup. It is really important to combine parts that belong to the same tuning level, this is especially true for cylinders, crankshafts and exhausts.
High End Racing products are exclusively designed for racing and should only be handled by tuning pros with the appropriate technical know-how. High-end racing parts often require modifications or machining of certain elements to accommodate the often larger components (larger crank webs, larger intake, etc.). Whether you stick with 50cc or increase the displacement, high-end racing parts offer much higher performance than the original parts and are the most powerful tuning parts.
Note: To ensure the reliability of the engine, it is important that the parts are compatible and that you do regular maintenance on your two-wheeler.
| Albero motore Stage6 HPC Derbi Euro 3 / Euro 4 corsa 44mm | |
|---|---|
| Article no. | S6-8019309 |
| EAN | 4051272039652 |
| Weight | 2,50 kg |
| Series | HPC |
| Brand | Stage6 |
| Product type | Crankshaft |
| Tuning level | High-end |
| Piston pin | 12 mm |
| Needle bearing | 12x17x15mm |
| Stroke | 44 mm |
| Conrod length | Standard |