I solved the puzzle. It's a Caloi Triathlon. Although Caloi is a brazillian brand, they ordered 200 bikes from Suntour in 1985 for their racing teams. It came originalli with suntour shifting group, sugino cranks and nitto handlebars. It's such a rare ride over here, it's a shame the paint is no longer original and i have no access to a full range of the components, I really like to looks and weight of the frame.
It was only made in this nice blue color.
A better look at the lugs on the top tube
Thanks for the chase, folks!