The TX750 was an engineering disaster, which was a shame as they weren't an ugly bike "back in the day". On my way home from school one day, I sat on my bicycle, fascinated, and watched one vibrate across the sidewalk on it's centre-stand and fall into the gutter, as it's owner and the Yamaha dealer almost had a punch-up. It's owner wanted his money back, and the dealer wasn't prepared, apparently, to grant him his wish.
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What you seen was an TX or SX650 vibrate like that, my brothers will do that. The TX750 had an internal balancer and was a very smooth running twin,(I have owned two of them), and a pretty nice bike overall.
The 73 model had issues with the oiling system that was a serious problem. It was fixed for the 74 model, but by then the damage was done and they sold very few and discontinued them.
And just in case anyone missed it, the original post on this subject is for ugliest "factory" bike. We have all seen really ugly bikes that people have made themselves,(I have one).
So in that spirit I ad, that most everything BMW and Moto Guzzi ever made to the list.