The 750SR was a special edition bike given to the top Miyata dealers in the country. It wasnt available to any other dealers and its not listed in any catalogs.
They were available in gold or a light to medium blue. Miyata had 3 tiers of dealers, gold, silver and bronze. I dont remember the exact breakdown but there may have been only 5 dealers in each category.
I dont recall if it was the top 5 dealers in the country or the top 5 in each tier who recieved bikes but each dealer was alloted 75. Regardless, I unloaded 75 of those from the back of truck one hot summer day.
Frame geometry was more like that of a 3 series bike versus that of an entry level 1 series. Think of it as bike with 1 series tubing and 3 series geometry and components.
For some odd reason $300 comes to mind and maybe '86 or '87 for a date.
Jim