Abstract: A balance system for a single cylinder engine is described. The single cylinder engine generates forces, that if left unbalanced, cause significant vibrations or movement to the single cylinder engine and devices driven by the single cylinder engine. The balance shaft includes a primary balance shaft for a first type of forces and at least one secondary balance shaft for a second type of forces. The secondary balance shaft is driven directly by the primary balance shaft. In one example, only one secondary balance shaft may be used, which may leave some forces unbalanced but is more space and cost effective. In another example, two or more secondary balance shafts may be included in a drive chain such that one secondary balance shaft drive the next secondary balance shaft.

Abstract: An apparatus and method for facilitating coupling of a fan and a flywheel, as well as an internal combustion engine and other applications for such apparatus and method are described herein. In one example embodiment, an apparatus for facilitating coupling of a fan and a flywheel includes a plurality of protrusions formed on the fan, wherein each of the protrusions defines a respective hole therewithin, a plurality of receiving structures formed in the flywheel, and a plurality of pins. The receiving structures are positioned so that, when the fan is axially aligned with and adjacent to the flywheel, the protrusions are respectively received by the receiving structures. Further, when the pins are inserted into the holes, portions of the protrusions expand outwardly so that interference is created between surfaces of the protrusions and the receiving structures, whereby due to the interference the fan and flywheel are rotationally coupled.

Abstract: An apparatus and method for facilitating coupling of a fan and a flywheel, as well as an internal combustion engine and other applications for such apparatus and method are described herein. In one example embodiment, an apparatus for facilitating coupling of a fan and a flywheel includes a plurality of protrusions formed on the fan, wherein each of the protrusions defines a respective hole therewithin, a plurality of receiving structures formed in the flywheel, and a plurality of pins. The receiving structures are positioned so that, when the fan is axially aligned with and adjacent to the flywheel, the protrusions are respectively received by the receiving structures. Further, when the pins are inserted into the holes, portions of the protrusions expand outwardly so that interference is created between surfaces of the protrusions and the receiving structures, whereby due to the interference the fan and flywheel are rotationally coupled.