hi john,that tester will not damage your magneto in any way,it will work fine just to tell you when the points break,same as a bulb and battery.
did you get your spare cylinder?i hope so.see you at the next jumble,good luck rick
Hi John, do you by chance have the name/contact of the person who had the 8 stud cylinder?. I have an early M20 with that barrel and would be interested.
Could you PM me on my home mail address please.