[corupter2]

Don't leave the covers off!
The first pebble that gets in there will shred the belt.
I've run that set up for years on all my Shovels. Hot as Hell here in Phoenix.
All I do is put a 1/4" spacer at each bolt on the derby and adjuster covers and leave the drain plug out.
Gives it just enough air to cool the belt and stator but won't let anything big enough to hurt the belt in.

 

[corupter2]

With the inner primary in place a small stone will destroy the belt. I've got 5 of them hanging on the wall.
There's 2 or 3 spots around the pullys where anything between the belt and pully will wedge the belt against the inner cover at rhe bolt bosses and rip it straight across.
Just my experience.
At $120 a pop for Kevlar belts it can get expensive.