Hi Richard,

Its difficult to say which one was the best or made the most improvement. I remember that the first mod was the carb change over to BMW carbs. this modification stopped the back firing that i used to get when on long trips and the engine got hot.

The electronic ignition improved the starting of the bike and smoothed out the idle.

The regulator and Rectifier mods improved the charging rate and stability of the output charge going to the battery.

So overall all the mods made a difference in some way or another. If you are having issues with your idel I suggest that you purchase a carb balancing manometer from your local bike shop and then spend sometime setting up the carbs and balancing them. ALso make sure they are balanced as you open the throttle. Check valve clearances if you have low compression ratio.