TX750 - The Troubled Twin

By the early 1970’s, Japanese manufacturers needed a cleaner running alternative to two-stroke street bikes and began to expand R&D into four stroke technologies. Yamaha – who had an enviable reputation for high performance two-strokes - first created the XS-1 650cc twin which was warmly received then, in 1972, launched the TX750, a bike that severely dented their reputation.

With a core mission to cancel out the inherent vibration of a large capacity twin, the TX featured Yamaha’s "Omni-Phase balancer" system which was, in fact a combination of two chain-driven counter-weight assemblies. Other innovations included a “failed headlamp bulb” indicator and even a rear brake shoe wear indicator plus aluminium wheel rims and rear lamp out indicator.

Civil and police versions of the TX750 were launched and, soon after, engine failures were reported while the complexity of the Omni-Phase assembly was questioned. Some speculated that the counterweights were frothing oil and this aeriated fluid starved lubrication to parts of the mostly plain bearing engine. Others questioned the oil filter assembly. Right or wrong it was a fact that Yamaha tried as much as they could to cure the issues including the fitment of an oil cooler even sending engineers to dealerships to examine and try to fix stricken machines.

It was not all bad news. The XS-1 became the XS650 and went on to become a legend while, sadly, the TX750 was quietly dropped by 1975. While much reverse engineering was done – and the final production of TX750 was largely trouble free - but the numerous initial engine failures cast a long shadow. Like any old Japanese bike, even the TX has a loyal following and parts are eagerly sought by enthusiasts.

Check out all the parts available for this rare twin on the CMS web site. We aim to take the trouble out of restoring this rare twin.