Finally, and at last, I have the twin points system running! First start was several weeks ago, just to prove that it would run, while I continued other work on the bike. It was a miserable rainy night so I poked the back end out the workshop door towards the neighbors fence, it started easily enough, ran it long enough for the return oil to appear, blipped the throttle a couple of times to confirm both cylinders were alive, then shut it down before the neighbors called noise control.
Then I fired it up about a week ago. Again, it started easily, but coughed & spluttered a bit as I staggered off down the road. However, after warming up and getting out on the open road, it cleared it's throat & ran well. In fact, there was a noticeable improvement over the tired magneto. It would drop back to 30 MPH in 3rd gear smoothly, without "hunting" and lurching as it had previously. Twelve miles was not a big test.
Today I got 128 miles of good riding in. Starts easily, in fact the points are clearly making sparks at kick starter push through speed, as it fired a shot on one lung with a part charge of fuel. Still a bit of coughing as it warms up, I'm putting that down to oil in the chambers having run down the guides while sitting for a week, which will make any spark system work hard.
Then on the open road it clears up and pulls well. There was no hesitation, or flat spots. It is happier at low revs that it was with the mag & factory ATD, it will drop to chain snatch speed, 40 KPH, in 3rd gear. It accelerates for passing similarly to previously, but without misfiring as it did with the mag. I was concerned about the advance range so I rode south to a hill known locally as the Lion's Back. This bike has always accelerated happily up there, but excessive ignition advance is easily exposed with the traditional pinking (Pinging for the Murcans) when accelerating hard.
It accelerated cleanly, & hard, passing a 1200 Sportster, at somewhere in excess of 140 KPH and climbing, according to my GPS.
Inspection when home indicated the points had closed a little to .017" so I adjusted them back to .020". I will put that down to heels bedding in and will monitor it. The points contact surfaces were clean & smooth. There was evidence of fresh oil at the bottom of the body, I will put that down to me over oiling the oil lite bushes, and monitor that also.
Conclusion; I'm hooked, overall the twin points system is performing better than the tired mag. I will continue to ride it, monitor the performance, and have the KVFTT repaired for future options.
The exercise has confirmed to me the opinions of a number of people, the factory ATD is less than perfect, particularly if it has done any serious work as most have, and there are more satisfactory options available to provide an improved ride.