Racing crankshaft for rotary valve engines - longer intake time for more revs, more agility and more power.
Racing Crankshafts are a simple and effective tuning step for any rotary valve engine. A Racing Crankshaft enables higher revs - the Engine becomes more lively and agile. The result is better acceleration and a higher top speed. Compared to the original Crankshaft, a Racing Crankshaft has a significantly longer intake time, which increases the degree of filling. The crank webs are streamlined and polished, reducing turbulence and stalling. Depending on the version, a polished knife-edge connecting rod is inserted and the lower connecting rod bearing is designed as a silver bearing. All Crankshafts are supplied with upper connecting rod bearings.
- More power thanks to extended intake timing and higher filling level
- Flow-optimized, polished cheeks and Conrods reduce turbulence
- High stability thanks to high-quality production and speed-resistant design
The high-quality Racing Crankshafts from the Italian company MAZZUCCHELLI impress with minimal manufacturing tolerances, low bearing play and a very good price-performance ratio. This guarantees high speed stability and a long service life. In addition, a subsequently fine-balanced version is also available: In this version, the Conrod oscillates at 12 Clock, which ensures very smooth running.
Racing Crankshafts from TAMENI offer a very good interference fit - another important basis for high speed stability and a long service life.
PINASCO and JASIL Racing Crankshafts have streamlined, polished cheeks and a high-quality, forged and polished Conrod. Both shafts are supplied with silver bearings and have additional lubrication holes or lubrication channels/slots for optimum lubrication.
PINASCO also offers the Competizione Racing Crankshaft, a sporty variant with sharper timing, flow-optimized surface, tungsten balancing weights and innovative PTFE inlays that ensure higher compression at low engine speeds - ideal for potent touring or racing set-ups. PINASCO recommends using the Crankshaft in combination with a lighter Flywheel or an electronic Ignition such as PINASCO Flytech, SIP Performance, PARMAKIT, MALOSSI or POLINI.
The JASIL Super Racing Crankshafts are considered an insider tip: in addition to the advantages mentioned, they offer polished lip cheeks with an intake timing of 124°/6° after TDC.
Another highlight comes from POLINI: Flowed Racing Crankshafts with an intake timing of 141°/6° after TDC, precisely balanced and with flow-optimized (= lipped), polished intake cheeks.
Conclusion: Not only useful in combination with a tuning cylinder - a significant increase in performance can be achieved even with an original cylinder.
Technical details
- Racing crankshaft
- Stroke 57 mm (PX), 42 mm (T5)
- Conrod 105 mm (125/150 cc), 110 mm (200 cc)
- Ø 95 mm Lima cheek, Ø 97.9 mm rotary valve cheek
- Shaft seal seat 24 mm, bearing seat 25 mm
- Blunt/thick Cone with M12 thread
- Lower connecting rod bearing: silver bearing (depending on version)
- Partially precision-balanced (12 Clock position)
- Including connecting rod bearing (top)
SIP tip
- New bearings, Oil Seals and half-moon wedges are mandatory, as well as a new Gasket Set and Clutch and Pole Wheel Nut. Racing Cylinders and exhaust systems such as SIP Road, SITO Plus or SIP Performance are useful additions. Adjust Ignition and carburetor jetting.