not to be a smarty pants, but
I ran Gspectro for years in my FJ1200. I traded that bike on a Valkyrie with 58,000 miles and it still pulled like a branded mule.
I changed the oil frequently, even tho the gspectro was touted as long drain.
I have seen some oil analysis on G spectro that are not so flattering. THe data suggests little ,if any, superiority to Auto synthetics.
Finally, I suppose any quality oil, motorcycle specific or not, (without getting into the wet cluch controversy)will suffice if it is changed regularly.
I did partially seize a CB900f once using valvoline dino in 90 degree weather. I was broke (in '89) That oil may have been ok for a thousand miles, but was dishwater on that fateful day.