What have you done to stop the dirt getting from the tire to under the seat. Because OEM exhaust covers the whole area under the tail but aftermarket ones don't. So the dirt with water goes through the unsealed holes under the tail.
I used silicone at the moment and it works great. Got one spot more to do after todays test run.
This is how it looked before:
Cleaned with air and hand. Alot dirt under the wiring.
This is the area it came from:
and under the tail: