Just spent a load of money on a 12k service in Triumph basically for a stamp in the book. On riding the bike back I found the rear wheel wanted to go in a different direction to where I wanted to go. On further inspection I found the belt was to tight and found the rear wheel wasn’t running true. Later after scrolling the forums it looks as if the Triumph Thunderbird 1600 (although a great bike) had a issue, seems that when the belt is sitting correctly the wheels is out and vice versa. Anyhow I loosened the wheel and took off the tension on the belt . Done a rule of thumb on wheel straightning and hay presto the bike runs fine. Moral of the story, the pros don’t always get it right !!