My New Year's resolution is to commute to work daily except school days, rain or shine.
Two MB's will be put to use; one is "The Dragon Lady", a dual-engined girlie cruiser. The other is "The Iron Dragon". Right now it's under renovation and waiting for "Bob", my 6hp push trailer.
I've been rained on a few times so far. Now I carry a raincoat and rubber gloves on the bikes at all times.
Friction drive doesn't work very well on wet roads. I'm converting to rear CVT or chain drive.
I don't pay attention to my engines in the rain. They run flawlessly even in heavy downpours. If traction is poor, then I pedal the bike and raise the engines off the tires.
I might clean the bikes off when the rains stop.