Portable Machine Engine with Overhead Valve has a lightweight structure and its toughness ensures easy handling and transportation. The Engine is available with a single cylinder and in air cooled version. The Machine Engine finds application in air compressor, rail drilling machine, rail cutting machine, pump sets, reaper, concrete needle vibrators, power trowel, soil compactor and concrete saw cutting machine. Portable Machine Engine with Overhead Valve is equipped with a recoil operated pull start system that facilitates ease of operation.