I am currently trying to get my grandfathers 1934 Norton model 19 (with a later 1946 model 18 engine) back on the road. The bike is now pretty much whole again and running, although I think I may have to get the magnito restored as I have a weak spark, anyway when I stop the bike the rectifier is sticking and the amp meter drops into the minus. Currently if I put full beam on and off it is enough to unstick it. Is this a serviceable part or could I cause more harm than good bearing in mind I am no mechanic. Thanks in advance.