I've run into a similar issue. I have a rephased 81 engine that I put back together over a year ago, but finially getting the rest of the bike finished. Now trying to get the motor dialed in and ready to ride. I have a Hugh's cam and crank and a Pamco ignition. When I checked the ignition timing I had to fully retard the Pamco to to get the left cylinder to 15 degrees. When I checked the right cylinder (made a separate TDC mark on the stator for that side) I'm getting a reading around 25 degrees. I only have marks at 15 and 40 degrees, so the 25 is a guess. I assembled the Pamco per Hugh's blog on how to do it and he said the magnets should be horizontal, sort of at 10:00 and 2:00 when installed properly. Mine were sligthly rotated counter clockwise, not much but a little. I can post picture later when I get home. Then I read this thread and decided to check the lobe center to see if my cam was maybe off by a tooth. I set the vavle lash at 0.012" per the clymer manual and put a dial indicator on the intake spring retainers. My calculations are as follows:
Left Cylinder - Open 32 BTDC, close 64 ABDC
32 + 64 = 96
96 + 180 = 276
276/2 = 138
138 - 32 =
106
Right Cylinder - Open 31 BTDC, Close 61 ABDC
31 + 61 = 92
92 + 180 = 272
272/2 = 136
136 - 31 =
105
Based on that it looks like the cam is in the correct position.
I'm not sure why i would get different timing reading between the two cylinders, doesn't seem like that is possible? Also why would I need to fully retard the timing if the cam is dialed in correctly? I had the Idle low enough, so it doesn't seem like I'm getting any advance and when I rev the motor the left cylinder advances to 40, so that all seems ok.
I know there are a bunch of ways to setup the Pamco, so I'm hoping I missed something and just have that wrong. Don't really want to have to pull the motor out of the frame and take it apart to change cam timing.
When I first set it up I put the degree wheel on and rotated the motor until I saw a spark and indicated the position at which that occurred. From what I remember that seemed to work. Then I saw Hugh's blog and figured I would just follow that instead to make sure it was right. It's been a while and I do believe I changed something from my original setup, so maybe I should have left it alone
Any guidance you could provide would be great.