I have a lot of TX750 experience. I was a Yamaha technician when the TX500 and 750 were introduced. Hopefully I can help answer future questions. I have replaced 10-15 engine cases on the 750s including on my personal 1973. I also installed the updated adjustable counter rotating balancer kits. I installed the double front brake disc kit and oil cooler kit on my bike available as Yamaha accessories. I later added BMW R90S handlebars, Dunlop K81s, Girling rear shocks,
and Dense Lube o-ring chain and nylon rear sprocket.