It's appears to be a positve crankcase evacuation system similar to what has been used in dragracing since the 70s. Usually a fitting in the exhaust is cut so as to cause a pressure drop in the attached hose which lowers the crankcase pressure and allows the use of very low friction rings without the problems that would normally be associated with their use (i.e flutter and oil control) on a standard engine with high crankcase pressure. The canister is likely an air/oil seperator , which also works as a check valve to prevent backfires and decel from firing the crankcase fumes.