Can I ask your opinion about using a strobe light to check the accuracy of timing on a mag ? At least one manufacturer's website does not recomend it but they do not explain why.
I have used my strobe powered by a separate bike battery
to check the magneto timing on both cylinders for years. I have scribed a line on the belt drive plate and marked up the cover in degrees. I find this is a very quick way to check timing after and during a meeting.
I use a vernier on the sprocket to adjust the timing on my Norton twin but confess that I have also used points gap to swap the bike quickly from petrol to methanol timing in the middle of the meeting when trying to run one bike in two classes.
If you set the timing at one extreme of recomended points gap range for petrol you can then get the 3.5 degree extra advance necessary for my bike to go to methanol. I can then check very quickly with the strobe that I have got it right. I know this means the flux peak (not the right words but you know what I mean) might not be optimal but the best I can do in a few minutes between races. This is on a Fairbanks Morse/Hunt/Morris type rotating magnet mag.
This is all usually done in a 20 minute organised panic of three guys swapping carbs, front brakes and ignition timing to move up from Clubmans to Open class. It has proved successful with a couple of seconds in the NZ Classic Senior TT on a upgraded Clubmans machine!
Any other suggestions gratefully considered.