I have a set from Yamiya750 too. Fit and look really good. I doubt that Honda did it better back in the days from 1969.
Sound is good to whithout diffusers. My engine must have them out, can't breath......
Good to know before assembly...
Important to fit the pipe correct on front spigot to make it fit at rear where the long bolt keeping foot peg and both pipes. No 2 was extra tricky... must be inside of the side stand.
The pipe must be swinged in place as much as possible on head spigot, banging with something heavy does not help, only destruction..
EDIT: If you have 4-1 since many years, more parts have to be ordered to install the 4-4.