Description
Polini EVOLUTION P.R.E. 4 – Racing Technology for Maximum Performance
With the new EVOLUTION P.R.E. 4 product line, Polini once again sets standards in scooter racing. Available in 70cc and 100cc, developed for scooters with Piaggio or Minarelli engines with flanged crankcases.
Polini PRE 4 Crankshaft
Part of the P.R.E. racing engine is the P.R.E. high-performance crankshaft with special balancing to ensure absolute stability even at extremely high engine speeds. The integration of numerous precision inserts allows exact fine balancing of the rotating masses, ensuring nearly vibration-free engine operation even at the limits. In addition, the optimized mass distribution enables the crankshaft to absorb the force generated by the piston as efficiently as possible and convert it effectively into rotational movement.
The crankshaft is supplied with an HQ connecting rod with lubrication holes and a silver-plated small end bearing.
The crankshaft operates reliably at speeds above 15,000 rpm and provides smooth engine operation, reduced vibrations, and the necessary durability for demanding competition use.
The 70cc racing exhaust should be used in combination with the precisely matched P.R.E. 4 cylinder and P.R.E. 4 exhaust and is intended for use with a high-end tuning crankcase (Malossi C-One, Polini P.R.E., 2Fast Passion, 8.1 Fireblade).
Polini Racing Engine - Perfectly Matched Racing Kit
The new PRE 4 set consists of cylinder, crankshaft, and exhaust, developed as a perfectly matched unit. The result is explosive power delivery and responsive throttle response even at low rpm.
A clear upgrade for riders expecting maximum performance, reliability, and consistent output throughout the entire race.
Details Polini P.R.E. 4 Racing Exhaust
- 70cc racing crankshaft
- Includes small end bearing for 13mm piston pins
- For Piaggio short (Zip SP) and Minarelli horizontal (Jog RR)
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.