Got this cheap bike from a friend for $50.00 just to get out and exercise and for another type of exercise. I've got things tightened up and got things mostly set where i want. My main issue is the handlebars keep moving on me. It seems the splines are kind of stripped \ have a flat spot. I have moved it and adj things then tightened the living crap out of the clamp on the stem too.
If it continues to move can a guy put athletic tape or anything around the bars to get them to stay tight?

They aren't moving nearly as bad as they were but today they broke loose a few inches when bouncing off some roots and rocks.
Any help would be greatly appreciated.