After L.C. Mason, of England, designed this water-cooled engine, he published a book on how to machine and construct a running engine. T.E. Murphy, of Phoenix, AZ, fabricated everything for this dual carburetor version in 1982, including his own spark plugs. The engine burns gasoline on spark ignition. it has a 19 mm bore with a 22.2 mm stroke. Total displacement is 24 cc. The Mastiff is 13”-long, 8”-wide, 9”-high, and weighs 13 lbs.