The right side because of that one motor mount on the left that is welded to the vertical frame tube. You cannot get past that mount if you are on the left side.
It has to rotate and angle just a bit and I always tape off the frames but ONLY with blue 3M tape as it sticks great and comes off great.
Now, if this is a new build and the frame is powder coated or nicely painted, place the right side of the motor DOWN on a flat surface, and maneuver the frame over it...
Good luck bud!!
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country