There is a german Oldtimer magazine, in almost every issue is a in-depth story about a particiluar engine. Engine is dissasembled, pictured and explained in detail.
Almost all italian motorcycles of the 50s to the 70s have a sort of centrifugal system in the crankshaft. The end of the oil bores wich lubicates the bearings is closed with a screw. In this blind hole debris collects. When you overhaul the engine, you should remove the Screw and clean the hole thoroughly.
I dont know if the engineers created this blind hole deliberately or if it was done because they could not machine the cranksahft otherwise back then. Today this blind holes simply dont exist anyomere or they are closed with a unremovable plug.
Almost all italian motorcycles of the 50s to the 70s have a sort of centrifugal system in the crankshaft. The end of the oil bores wich lubicates the bearings is closed with a screw. In this blind hole debris collects. When you overhaul the engine, you should remove the Screw and clean the hole thoroughly.
I dont know if the engineers created this blind hole deliberately or if it was done because they could not machine the cranksahft otherwise back then. Today this blind holes simply dont exist anyomere or they are closed with a unremovable plug.