Ok, I am done for the weekend and appear to have had success.
I think 21mm is just about the magic number for the springs, or any similar length that makes them not rattle loose, but not pressure the weights when at rest either. Tight enough to remove play from the cam, but no tighter.
The bike advances normally now, smoothly, and without hesitation. It's advancing to 5 degrees past the two marks, but I am not thinking that is enough to worry about.
So, the tally for this weekend is pulling engine, change advance springs, replace three oil seals right side, change starter, switch, and solenoid, paint and install right and left covers (replaced the right one that was cracking), reinstall engine, and then one more thing I am afraid to even mention.
Just for fun, I installed the Amal 626 carbs I bought a while back - when I thought my carbs were toast.
Followed the instructions on the forum, bolted right on, and shaved down 14mm of each cable housing at the splitter. Removed the choke circult and capped the 2nd hole on top of each carb.
Hit the primers twice, one kick and WHAM it took off running like crazy.
Tuned the idle screws down and got a smooth, stable idle at 1200.
Jumped on and took off, and I mean took off.
Like a totally different bike.
I know its completely heretical, and I will be shunned, but these carbs are the shit.
I am never going back.
No lag or spitting off the line - just power and lots of it.
No adjustments made, and the plugs are deep brown and happy.
And they are just enough smaller than stock that you can fit pods on if you wiggle it around the petcock.
Picture 007 by
Jrlovvorn, on Flickr
Picture 005 by
Jrlovvorn, on Flickr
Picture 009 by
Jrlovvorn, on Flickr