Hi, I assume you are talking about radial clearence between the rotor and the stator and the problem is that the rotor is not in the middle?
Here is what the experienced guys at the Norton Sweden Club recommended me to do (and successfully did).
1) The 3 mounting holes in the stator are approximately 8 mm dia. Increase the size to 9 mm by drilling. This will allow the stator to be adjusted in position with regards to the rotor.
2) Cut out a piece of a "cornflakes box", make it the size that would fit inside the stator (will act like a flexible paper shim in between the stator and rotor)
3) With the "paper shim" in place, push the stator over the rotor and the paper shim will give you an even 360 degrees clearance between the stator and rotor and the increased size (9 mm) stator mounting holes will allow the stator to move as needed.
4) Leave the paper shim in place. Now you can "seal" the extra clearance you have in the 9 mm stator mounting holes with "epoxi" or something else (I used selected pices of lockwire held in place by strong Loctite). There is different opinions on what is the best. Your call!
5) Fit the stator mounting washers (use the old thick type). Loctite and tighten the stator nuts per the workshop manual.
6) Remove the paper shim. Now you are done
You should get a better charging effect and even if the bike is left unused for long periods of time the rotor magnetism won't be negatively affected in the same way as when the rotor is much closer to the stator at one point.
Regards,
Per