Engine secondary balancer system

An engine secondary balancer system includes a balancer housing (41), a pair of balance shafts (44, 45), an endless transmission belt (47) for transmitting rotational power from a crankshaft and a hydraulic tensioner (49) for imparting a tension to the transmission belt (47). A lubricating oil passageway (68) for introducing an oil between upper and lower housings (42, 43) and the pair of balance shafts (44, 45) is provided so as to communicate with an oil supply passageway (70) provided in a crankcase (14) viaanorifice (69). Atensioner oil passageway (71) for introducing an oil to the hydraulic tensioner (49) is provided so as to communicate with the oil supply passageway (70) at a position upstream of the orifice (69).