Yamaha 1974 TZ 750A production racer 694 cc 4 cyl TS 3601

Yamaha 1974 TZ 750A production racer 694 cc two stroke liquid cooled four cylinder frame & engine # 409 000 158

The Yamaha TZ750 is a series production two-stroke race motorcycle built by Yamaha to compete in the Formula 750 class in the 1970s. The engine was created on the idea of connecting two blocks of the 2-stroke, liquid-cooled, in-line 2-cylinder TZ350 engine together to make a 700cc in-line 4-cylinder engine and mounting it on a newly designed high-tensile steel pipe double cradle frame.
Motorcyclist called it “the most notorious and successful road racing motorcycle of the 1970s”. Another journal called it the dominant motorcycle of the era, noting its nine consecutive Daytona 200 wins, starting in 1974.
A factory spec TZ750 (0W19) won its debut race in the 1974 Daytona 200-mile Race ridden by Giacomo Agostini, and it also went on to be a winner on the Japanese and world racing scene as well.
The first version, the TZ750 A, had a cubic capacity of 694 cc with bore x stroke dimensions of 64 x 54 mm and dual shock rear suspension. Later versions got a slightly larger bore of 64.4 mm and came to a capacity of 747 cc. These versions were fitted with a mono shock rear suspension. The power (89 hp @ 10,500 rpm for the A version) was transmitted to the rear wheel via a 6-speed gearbox. The last version, brought out in 1979, had an output of 120 hp.
The TZ 750 was not easy to ride and required a skilled an fearless rider. The factory was aware of this, but it had to build at least 200 machines to comply with AMA rules:
“Yamaha quite naturally has reservations about selling TZ750s to just anybody with money and a bag of brave pills. But AMA rules require 200 copies and you can’t expect them to simply warehouse the production left over after Kel Carruthers takes what he needs. All the big fours will be sold, some of them to riders whose talents were barely equal to last year’s TZ350. That thought plainly has the AMA spooked, because they know they don’t have 200 Juniors and Experts who can cope with what it is feared the Yamaha will deliver. But there’s nothing to be done now; Yamaha created the TZ750 in good faith and strict conformity with rules long-standing if not necessarily wise.” — Gordon Jennings, Cycle, January 1974
How the TZ750 came into being is explained by Frank Melling:
Memorable Motorcycle: Yamaha TZ750A – Motorcycle USA
Our machine was purchased new in 1974 in Germany at the local Yamaha dealership in Dortmund by local entrepreneur Klaus Völkmann. Together with the machine he bought a set of 500 cc pistons and cylinders, so that it could be entered in two classes. His friend Hans Otto Butenuth ( TT Classic Section – Under the Chequered Flag, Hans Otto Butenuth ) raced the bike during the 1974 season. Its fierce nature was a bit much for him and for the 1975 season he changed to another make. At the end of the 1974 season the machine became part of Völkmann’s vehicle collection and hasn’t seen any racing since. In all, 213 TZ 750A machines were produced in 1974.