My cuckoo clock runs fine until I attach wooden pendulum?

The wire thingie connected to the gears swings and keeps going, but as soon as I attach the wooden pendulum (even without the sliding weight), it stops. It is perfectly level and even if I tilt either way it won't work with that extra weight attached. I've tried cleaning with canned air and used graphite on pivot points of gears. That made the cuckoo and music run much better but did not effect the pendulum.