Milling overflow channels for Vespa PX engine

The Vespa engine - The heart of Platónika - received the desired crankshaft control angles in the last article

Adjust cylinder overflow channels in the engine to optimize performance

Vespa tuning: Before the engine can be completely reassembled, all work that produces chips must first be completed. Only then can the housing be cleaned. In the next step, this includes the overcurrent channels of the cylinder in the engine. The BGM177 is designed so that the cylinder also works perfectly on the original overcurrent channels. In our project, however, we take the opportunity to adapt the housing directly. A better filling of the cylinder always means a higher possible torque. The easiest way to transfer the contour of the overflow channels to the motor housing is to place the matching cylinder base gasket on the housing and thus transfer the contour to the housing. The sealing surface is best marked with a foil marker. The contour of the overcurrent channels is then marked with the aid of the cylinder base gasket. The contour in the motor housing is then adapted using a milling cutter. It is not necessary to mill the channel to the same depth as in the original engine housing. The BGM 177 cylinder is designed in such a way that the piston has a sufficient cross-section. The surface of the adapted port can be as rough as you like. Further polishing is not necessary. As long as there are no rough corners and edges, a slightly roughened surface is perfect. Once the channels have been milled and the housing has been cleaned again, assembly can continue...