I have found a couple of instances where starting became hard with the new BTH mags, the one I struck was on a customers Black Shadow that has always been a good starter. Though I do know he keeps the bike in a shed where moisture is not uncommon. When he brought the bike to me last, he complained of hard starting which surprised me a little, so I gave it a go, and true enough it would not start. After a small amount of brain scratching, I decided to remove the end cover off the BTH
(the instructions tell you not to do this, but that never stopped me before) anyway what I found was the two pole pieces which form the primary part of what is basically like a CDI unit where lightly covered in rust .......!!!....Out with the Dremel and a small wire brush, I polished the ends of the pole pieces, wiped them with a clean rag, and refitted the end cover. The bike started first kick, and again, and again, no problem. So the slight build up caused enough resistance to create a descent spark at kicking speed.................. Now there's a lesson for you all............