Engine and drive belt cooling system for an all terrain vehicle

An all terrain vehicle having a belt driven type power transmission including a drive pulley means mounted securely on a crank shaft of an internal combustion engine of forced-air cooling type, an engine cooling fan means having an air intake suction side, said engine cooling fan means also being securely mounted on said crank shaft, a driven pulley means mounted on a driven shaft means, and a drive belt means extending operatively across said drive and driven pulley means;

• wherein said driven and driven pulley means and said drive belt means are enclosed hermetically within a casing means, comprising in combination an air suction fan means mounted integrally with said drive pulley means, a first suction duct means adapted to introduce outside air into the side of suction or negative pressure generated by said air suction fan means and connected operatively to said casing means, said casing means having an air outlet means located intermediate said drive pulley means and said driven pulley means, and a communicating pipe means operatively connecting said air outlet means to said suction side of said engine cooling fan means.