Silicone seal the back side of the CDI. I bought some soft rubber sheet and Gorilliaz Glued it on the back. Hopefully it will slow down vibration input as well. But waterproofing was the goal, don't forget to put silicone deox jelly in every wire plug and connect you can, including the spark wires, both ends. I made it through a flash flood in the desert a few years back without a stutter, and yes I prepped for it.
