If you remove the points from the plates and loosen all three large plate mounting screws, you will find that that large plate will move some distance radially on the mount posts machined into the engine case. This movement is why you run out of adjustment range, as some plates are different diameters, and some engines have been machined to a different tollerance limit. The spring pressures of the points pushes the plate in the opposite direction against the mount post. This puts both points in a position relative to where adjustment range is limited.
What to do. While you have the points removed from the plate (thus all spring tension) and all three mount screws lossened, find the largest feeler gauge that will insert in the gap between mount post and large breaker plate. This is also the point gap error and directly impacts timing. Reinstall the 1-4 points, set the gap and the 1-4 static time with the feeler gauge still inserted in the lower right mount post to breaker plate gap. I sacrificed a feeler blade and cut one in an L shape to fit under the mount screw washer, so it wouldn't fall out during plate rotation. This way I can change the 1-4 timing while the bike is running (dynamic timing) or not (static timing). In my experience, this brought the adjustment slot for both 1-4 and 2-3 points into an acceptable adjustment range.
How did I figure this out? Well, the bike showed me this problem. One day, while trying to dynamically time the engine, I had all three mountplate screws loosend while the engine was running. It was then I could see the whole friggin plate moving around in the engine posts. Dwell readings were all over the place, too, depending on which mount screw I tightened first or when and where the engine crankshaft was positioned when a mount screw was tighened. Putting the plate in a stable position eliminated all the variability of time and dwell. Then I found that if selected the right post to remove the excessive plate movement, the adjustment ranges of the slots were more than adequate. So, I made a new tool, and, added it's use during the adjustment procedure.
Life is good.
Cheers,
