I was wondering how do go about testing the compresion on an 2nd gerneration non turbo rx-7?

 

buy the tester.
take spark plug out and put tester in
take out the EGI fuse to cut fuel
have someone turn motor over while you watch the guage
you want to see 3 even bumps for both the 1st and 2nd rotors
they should all be over 100psi if motor has good compression (7.8kpa??? or so)

 

You forgot to throw in "hold the throttle all the way open when cranking."