Two-stroke owners have it easy. In order to lubricate their engines, a little bit of oil is mixed in with the petrol and this petroil mix is drawn into the carburettor and becomes a vapour. From the carburettor, this vapour is sucked into the crankcase, where it has a dalliance with the main and big end bearings, before being pushed up into the barrel to lubricate the piston, and, finally, this busy vapour is compressed and then exploded. With its job done, this oily mix is pushed through the exhaust system. All simple and requires a measuring jug to ensure the correct quantity of oil is mixed in to the petrol.
This of course ignores the autolube systems which feed the oil direct to the bearings and
