I installed a tail tidy / fender eliminator on my 2019 r3. After the install i couldn't help but notice the hole that the wiring passes through will allow allot of water in that splashes up from the rear wheel. How has everyone solved this?
If/when you ride in the rain, water will find it way into the tail section. It doesn't really matter what you do to "weather-proof" the hole the wires pass through..... Yamaha engineers actually do a pretty good job at protecting the electrical components on the R3. Most, if not all of the wiring is very well protected from the elements. I wouldn't worry about it-
use a rubber grommet, i usually pick mine up from homedepot or lowes, just gotta find one that fits. i had some laying around in my parts bins and just trial and error until i found one that fit.
trick is to run the wire through the hole first, them slip the grommet over the wire then into the hole, if you put the grommet in first you will most likely not get the connectors at the end of the wires to pass into the hole.
TST Underfairing plate won't waterproof things but it does block off the large opening left in the under fender by the tail tidy. Helps divert water nonetheless and looks very finished. Undertail Fairing | Yamaha R3 & MT-03 2015+