Yamaha was watching closely Honda do the investigating research, development and marketing and thought of reviving the thumper crossed their minds, After thoughtful research Yamaha came out with TT500, to be produced in both street-legal Enduro (XT), and play bike (TT), configurations, the new 500 ohc four-stroke from Yamaha is a tremendously versatile and an appealing machine. The engine is a straight-forward two-valve Single. Bore and stroke measure 87mm x 84mm, yielding a total displacement of 499cc.
The overhead cam is run by a chain off a sprocket on the right side of the motor. Chain pitch is identical to that used on the Yamaha 650 Twin. Tension is maintained by a rubbing-block tensioner that is easily adjusted from outside the engine.
The camshaft itself is supported on both ends by ball bearings. Feeding the bike is a 34mm Mikuni carburetor.