Re: What does rain do to a MB?
I've done the RTV things others have suggested on all the gaskets, CDI/plug wire, magneto, and probably a half-dozen other places I can't think of right now along with soldering and shrink wrapping the wire connections.
I have ridden through some intense downpours with no ill effect.
Things did tend to rust a little but since I started spraying a little Remington oil over everything every couple weeks, I haven't seen the problem worsen.
You probably want to keep things covered while it rains but if you seal everything up and keep it as dry as possible it can be done.