Help identify my bike frame
That's definitely a Japanese frame and my guess is the wheels were an upgrade somewhere along the line.  The mix of Shimano and Suntour also is unlikely to be how the bike was sold. My guess is the Cyclone derailleurs were an upgrade, but since it's friction shifting it all plays fine together.

A web site with a lot of experts is the "Vintage Cream" Facebook group.  I would suggest adding more closeup pictures of the lugs, fork and bottom bracket. Tange #2 and Shimano forged dropouts are clear indicators of a very well made frame.

Vintage Cream FB Group

Good luck in your search,
Greg