Air-cooled engine for general use

The objective of this invention is to solve two sorts of problems in an engine using a chain transmission scheme with the camshaft (24) as the output shaft. One set of problems results from the stretching of the chain (27). The other concerns lining up the crankshaft (23) and camshaft (24) during assembly. With this invention, power is transmitted from the crankshaft (23) to the camshaft (24) by means of a silent chain (27). The said silent chain is tensioned before use to suppress its initial tendency to stretch. The chain is installed so that the slack in the chain is 1 to 2% looser than its theoretically calculated distance value between the crankshaft and the camshaft. (A chain tensioner is not used.) One or several marks (Mc, Ms) are provided on the opposed surfaces of the aforesaid silent chain (27) and the two sprockets (25, 26) to help match the positions of the crankshaft and camshaft.