You have to remove the heat sink from the top of the engine's cylinder head, and look at the top of the piston.......

you'll find the CG there EVERY TIME, I PROMISE ON MY WIFE'S LIFE

It's a tiny little golden nugget that speaks in an irish accent and it calls you a "Crack Gigolo"
(jk)
(look for the 1st wingspar and go about 3 fingers back from there, pick up the plane by the wings at this point CLOSE to the fuselage. If it tips forward or backwards, ALOT, it's a problem you've got to fix before you get the plane in the air! I know this because I have a plane that is TOTALLY BUTTHEAVY!!!!)