The 800 trails and 500s share the chassis and suspension. Both ride like a buckboard even at best IMO. Changing the springs and/or shocks was the best thing I ever did. It even lead to my wife riding with me again...lol..hmm. Before that though I achieved the best ride I could by: First setting the rear spring preload so as the suspension rode mid-way in it's travel when loaded with all the people and stuff I normally take. Then, as there is no compression adjustment, setting the rebound where the valve was closed..ie to the right then open it three clicks. Then the front was set to be level to .5"s lower then the rear loaded. As the front has compression and rebound, compression was set to the center position then to the left or open 1-2 more clicks. The rebound was set the same as the rear.
The CFM springs suck and even getting the Bandit set was a night-n-day improvement. Smooth and compliant..like riding on a cloud compared to the OEs.
Also try lower tire pressure. I run between 7-9psi depending on conditions.