Just watched your video and it's great...that motor sounded fantastic...I'd be really curious as to what happened?
There are very few things in life more enjoyable than riding a good Triumph Bonneville from the golden age, IMO. It's like driving a 1970 Porsche 911S, just a sweet spot in time when engineers had no constraints other than maximum performance using old technology. Engineering over design but the design wasn't bad, either.