This was the last of the Air Cooled race machines from Yamaha, starting with the TD2 250 of 1969. The TR3 had a revised bore and stroke of 54mm x 54mm giving a true 347cc and 58BHP @ 9500 RPM. This allowed it to compete with the all dominant MV3, and achieve one of the biggest race upsets of all time when it won at Daytona with Don Emde in 1972, beating 500 Suzuki twins and 750 Kawasaki triples. This race machine was a true milestone, and made four stroke machinery completely uncompetitive, especially when the water-cooled TZ machinery arrived the following year. Two stroke race machines dominated, until a change of ruling came about some 30 plus years later, allowing the modern Moto-Gp formula to return to four strokes. Not a bad run though!
