Description
Polini Motor Pack: Alu Cylinder + Crankshaft with Bearings 80cc Derbi D50B0
With this exclusive Polini tuning kit you get a perfectly matched combination for 50cc motorcycles with Derbi Euro 3 / Euro 4 engine. The set combines Polini’s most powerful 80cc aluminum cylinder with the matching reinforced For Race crankshaft and high-quality bearings. The advantage of this kit is clear: all components are technically matched to each other, which makes installation easier and ensures maximum durability with impressive performance.
High-End Performance: Polini 79cc Aluminum Cylinder
The core of the kit is the aluminum cylinder manufactured by the quality foundry Gilardoni, featuring a 50mm bore. With a full 80cc, the cylinder with 5 transfer ports and exhaust with boost ports offers a significant performance increase compared to the original setup. The high-quality ASSO piston with two piston rings ensures optimal sealing and durability. As with all high-performance aluminum cylinders, correct squish clearance adjustment is essential for full performance.
Maximum Stability: Polini For Race Crankshaft and HQ Bearings
To reliably transfer the power of the 80cc cylinder to the road, the tuning kit includes a reinforced Polini For Race racing crankshaft. The CNC-machined connecting rod is extremely robust and designed specifically for tuned engines in the 50 to 80cc range. The package is completed by a set of NTN C4 crankshaft bearings with a steel cage and special Viton oil seals. These HQ seals are highly heat-resistant and polymer-coated to minimize friction and wear under racing conditions.
Contents of the Polini Tuning Kit:
- Polini aluminum cylinder kit d=50mm (79cc) with ASSO piston and 2 rings
- Reinforced Polini For Race crankshaft with CNC connecting rod
- Silver-cage piston pin bearing (12x15x15mm)
- 2x NTN C4 main crankshaft bearings (6204, 20x47x14mm) - Journals: 20/20mm
- 2x Viton oil seals (20x35x7mm) with polymer coating
Note: Spermotos / enduro bikes with Derbi Euro 4 engine use a slightly smaller temperature sensor (thread: M12 x 1.5) than the Euro 3 models (M14 x 1.5). To mount the smaller Euro 4 sensor on the cylinder head, you also need the adapter MF96.91010.
Tuning Level: 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.
Racing products are designed for a more extreme uses and are developed primarily for racing. Whether you stay at 50cc or increase the displacement, the corresponding Racing parts produce much higher performance than the original parts in order to achieve maximum power.
Aluminium cylinders
Aluminium cylinders are more powerful than cast iron cylinders, but require more regular maintenance and must be combined with different components such as a reinforced crankshaft and a larger carburetor.
How to run in an aluminium cylinder?
Aluminium cylinders should be run in for about 200 kilometers , and you should use a fully synthetic engine oil.
Note: To ensure optimum performance and reliability, it is advisable to measure the squish clearance. Just have a look at our tutorial How to adjust squish clearance.
