What better way to discover and solve your teething issue than a run to the Ace Café lol. The turn out so far is a disappointing 4.
If you have swapped the HT leads over and the same problem exists then that tells me your ignition system is fine.
Have you had the carbs balanced? Being a twin they are very sensitive to this.
Also what is the condition of the carb rubbers? An are leak can also cause running issues and at 36 years old rubber will be perishing. Also the diaphragm in the right carb maybe faulty. A reasonably accurate and quick check is to lift both sliders through the airbox side and let them drop at the same time. They should drop at the same speed.
