Had two of these back in the day, I had good results until the CR came out :-) I think if I could go back in time I'd go the Yamaha with reed valve and up pipe they really were ahead of their time.
So what was the attraction to ride a modified TS 125 in 1975
(as per your avatar pic )
As for Daves question for me it is the KX 125 or possibly the Elsinore