There is a clear spray sealant made by CRC to waterproof ignition systems, after it's applied, it dries like a clear plastic shield, works great.
I use it on my boat engine, you can find it in auto parts stores. Make sure the bike is warmed up and dry,
spray all your wires, but don't get it on your points like Ray said.
You can usually spot old/cracked wires jumping spark when it's damp and in the dark, or by feeling the wires while it's running, you'll get a shock but it won't kill ya.
hell, I enjoy a jolt every once in a while, yep.