Mounting device of cam chain guide

An internal combustion engine, comprising:

• a cylinder block having a cylinder bore therein;
• a crank casing;
• a crank shaft and a cam shaft provided externally of said cylinder bore;
• a cam chain for transmitting rotation of said crank shaft to said cam shaft to operate an intake/exhaust valve through a push rod and a rocker arm;
• a cam chain guide;
• and
• a mounting device for said cam chain guide, said mounting device comprising:
• a first protrusion provided in a vicinity of a lower end of said cam chain guide, said first protrusion being fitted into a first locating groove provided in a vicinity of said crank shaft in said crank casing;
• and
• a second protrusion provided in a vicinity of a an upper portion of said cam chain guide, said second protrusion being fitted into a second locating groove provided in a lower surface of said cylinder block, said second protrusion being gradually enlarged from an innermost portion towards an opening thereof.

A method of mounting a cam chain guide in an internal combustion engine, the internal combustion engine including a crank shaft and a cam shaft provided externally of a cylinder bore, wherein rotation of the crank shaft is transmitted to the cam shaft by a cam chain to operate an intake/exhaust valve through a push rod and a rocker arm, said method comprising the steps of:

• providing a first protrusion in a vicinity of a lower end of the cam chain guide;
• providing a first locating groove in a vicinity of the crank shaft in said crank casing;
• fitting the first protrusion into the first locating groove;
• providing a second protrusion in a vicinity of a an upper portion of the cam chain guide;
• providing a second locating groove in a lower surface of the cylinder block, said second protrusion being gradually enlarged from an innermost portion towards an opening thereof;
• and
• fitting the second protrusion into the second locating groove.