There are a couple of triangle brackets and I assumed they were for the top flange.
I could be wrong and didn't take my time holding in place to make sure the top brackets lined up. I could be way off with the motor.
He also has an old coleman 5.3 with the sachs, and that motor is out of the bike as well, but I know that the sachs goes with the coleman. so taking the Chaparral out of the equation, I still cant find a frame that matches this one. Sorry for the confusion. I am not by the bike, I am gong to have my brother check it out tomorrow, and hopefully we can figure it out.