The Hyosung 650 engine is almost a direct copy of the Suzuki SV650 engine. One of my best friends is a Triumph dealer who sells Hyosung’s. He hopped one up to race in local club races and his rider does very well on it.
It isn’t that similar, except that both are 650 v twins.
There are no interchangeable parts.
The Hyosung GT-650R is a good bike for racing with a heavy but solid frame that makes it an excellent corner carver. Some buddies of mine in England have raced them at Brand’s hatch and it will embarrass most Japanese bikes in the turns. We’re hunting for the right set up to embarrass them on the straights as well.