I live in a desert, and when rain is forecast, I drive my truck. The wiring on my scoot accumulates in a bunch of connectors on the right side of the frame. The plastics on my scoot have a vent that opens right on the electrical connection bundle. If it was raining, the water would be funneled into the electric bundle. I have thought about making a waterproof enclosure for the connectors. I do coat every connection with dielectric grease. How do you handle the problem. You have much more rain than we do.
I was thinking something more permanent. I could use a freezer bag, but that is a little ghetto. First thing I did was mount a flap on the plastic intake to funnel the air toward the engine where it should go. The di-electric grease will most likely work for the little rain we get here. (over 300 days of sunshine per year here). Just a stupid design.
I wouldn't go more permanent, you will need to take the plugs apart at some stage. However, you can buy a water tight box, marine type, to house them in. Trouble is you may need to either extend the wiring and/or find a place to mount the box. Personally i'd go with the heat-shrink tubing, its what i've done on my 1100, over all the plug fittings, easy to remove and easy to replace.
If you have some old bicycle inner tubes, cut some long strips from that and wrap it around the wiring like a bandage. You can tape the ends with insulation tape. Do we have to think of everything?
How about finding out where the flow of water would start (which leads to your bits getting soaked!) & set up some sort of deflector/diverter.?.