i'd look over the rear end the axle carrier and axle itself. make sure the bearings are all good all around just so you know what your getting into. check the sprockets out make sure they aren't hooked like should look the same on both sides of the teeth if not might need to be changed.
And why do you need to do a compression test when it is hot. If you ask me that would be the worst time to test it since metal expands when its hot