You do realize the Compact & TriStar CXL use an ordinary Ametek double-stage motor, like the ones found in older Kenmore & Filter Queen canisters, right? Not much to really do there....the only thing you can really do is change carbon brushes or take an armature stone to the armature. The carbons are really easy to change, as it's just held in place with a metal bracket & 2 screws, & a clip that slides into the brush from the motor.
The fan blades & top or bottom bearings can be changed, BUT unless you're an expert at rebuilding motors, that's best left to a local vac shop. And by the time you are done paying their fees, you might as well throw a little bit more money at it & just buy a brand new motor.
When you go to take the motor out of the TriStar, make a quick note of how it's wired up, so you can put it all back together of course. It will be easy, though....the TriStar is one of the simplest, easiest designs to work on ever made.
Best of luck....Rob