Compression Testing
 

Simple question : How exactly do you test the compression in a rotary engine?

You can take it to the mazda dealership...

Or i THINK you can use a normal compression tester and u watch the bumps on the gauge everytime the seal passes by the spark plug hole... Correct me if i'm wrong people

yeah, but if you do the poor mans compression test you have to take out the little needle thing at the end of the hose ya know the thing what would release air from your tire. well you take that out of the compression tester and put it in a spark plug hold and take the EGI fuse and have somone crank it

pulling the valve out of the gauge prevents the gauge front holding the highest reading. A rotor has 3 sides and to read all 3 sides, you have to let the air out so the gauge goes to zero. that way, if your first reading is 110, the pressure will go to zero so you can see if the next reading is 30. With the valve stem in there, the reading will not drop below 110 (or what ever the highest reading is).