Such variable stroke engine has already been known as disclosed in Japanese Patent Application Laid-open No. 2003-278567.
However, in the variable stroke engine disclosed in Japanese Patent Application Laid-open No. 2003-278567, the camshaft is disposed at a position relatively spaced apart from the crankshaft for the purpose of avoiding the interference between the end portion, on the camshaft side, of the link member and the intake-side or exhaust-side cam. For this reason, the size of the crankcase, and further, the size of the entire engine is increased.