Engine rotation angle detection device arrangement configuration

The configuration has a detection plate (51) fitted to a cam shaft (14) of an engine (11) and rotating in an integral manner with the shaft. A sensor detects a detection part (56) provided on the plate. The plate is arranged so as to be positioned between cam parts (25) of the shaft. The plate is arranged next to a sprocket driving a cam chain. The plate and the sprocket are tightened with respect to the shaft.