There are 4 allen head
screws on the back side of the wheel pilot on the top half. Loosen them, which allows the idler wheels inside to loosen. Once loose enough you can pry the drive wheel off.
Then reassemble and tighten the allen head
screws. Sounds easy. It's a tad tricky.
If you experience the joy, where the screws just turn and don't tighted, chants are required. I have fixed that by drilling a 1/2" hole in the drive wheel centered about 5/8" from the edge (does not matter where though I did mine at the bottom), which allows a small socket or needle nose plyers to hold the tiny nut at the other side of the idler wheel.
Also good to lube the metal clutch bit that the tension pulleys ride on.