Standard crankcases can undoubtedly be improved: the aim is to facilitate the flow of the air-fuel mixture. In fact, after CNC machining, certain areas of crankcases have imperfections, especially the intake: the tuner sands down the surface and removes any chips left over after fusion, thereby improving the fluid dynamics and, therefore, engine performance. Particular attention should also be paid to the coupling with the cylinder: the crankcase has a sort of "ramp" to channel the air-fuel mixture into the transfer ducts, which then create the combustion. This particular channel between the crankcase and the cylinder needs to be cleaned and connected to improve it.
Tuners do not simply clean the duct of aluminium residues, but, depending on their knowledge, they can mill the crankcase, thereby removing material and modifying its volume. If we succeed in increasing or decreasing the quantity of fuel inside the crankcase, surely performance changes. On crankcases, work is almost exclusively concentrated on the intakes, which is where a tuner can have the greatest impact. You also need to pay attention to the assembly of the crankcase, which is normally overlooked. It is essential for the two sides of the crankcase to fit together perfectly without using too much force. Therefore, we recommend not hurrying too much and taking great care when performing the reassembly.