Ken, back in the early 80's I was running a M/C shop service, repairing and rebuilding British M/C's
The single hardest part was locating good original parts to rebuild with.
When I started to modify my 1975T160 Trident, I kept all of the original parts, so today all these years later I could restore it to original 1975 condition.
The only component that I don't have is the original mufflers, but I know someone that makes those 
Viking Exhaust : Part Detail