ever heard of a MAXIM-X?

Answer 1

Yep, Yamaha Maxim X
Two models built; XJ700X and XJ750X. Fairly rare bike, not too many brought into North America, only for two years; '85 and '86. Probably more of the 700's around than the 750's because the 750 was not allowed into the US market, and was only in Canada. The main difference between the regular maxim and the X model, is that the X model has a 5 vavle head, where the typical bike of the day had either 2 or 4 valves.

Answer 2

Yamaha make a Maxim, never heard of Maxim-X though