After reading most of the responses I am surprised no one mentioned wheels. Find a good wheel builder and have your tuned up. Odds are you have loose spokes. A common problem with dirt bike wheels, when I was racing hare scrambles and cross country races I would have my wheels tuned up every year.
I'm NOT surprised no one mentioned wheels. My '03 has 63K miles on it and I have changed my own tires and checked the wheels for all but the 1st 17K with no indications that spokes have loosened or that either wheel needed truing. It's pretty easy to check that before finding a good wheel builder from my very limited experience in wheel builder finding. Do you have a friend that is a good wheel builder? ;-)
I agree with those that suggested suspension is the 1st place to address the OP's complaint.
I'm also curious why your 1st post on the site wasn't something about the very useful invention mentioned on your profile page and hope you'll start a new thread about it!
Last edited by Vgraf; 04-23-2020 at 08:21 PM.