handlebars loose. damaged handlebars/stem?

I was fiddling around with my (2nd hand, well used) bike the other day. I removed the handlebars from the stem. There was something wrapped round the handlebars, under the stem. It was like tin foil, but a little thicker/more substantial.

I threw the 'tin foil' away. Now I cannot get the handlebars to stop moving. I have tighten the bolt in the stem as much as possible.

Any ideas guys?

many thanks.

You've thrown away a shim, or something used to compensate for the difference in clamp sizes of your bars and stem - the stem will have a bigger clamp than your bars, so without the shim your bars feel loose. No amount of tightening will change it.

Just make another one using a strip from a can to plug the gap.

a can. Yeh, that was the kind of stuff it was.

so, the clamp sizes are different? Gosh, there can't be much difference. I can ride it fine. The handlebars slide slightly to the right after a few miles/bumps.

Thank you!

Most likely there's only 0.6 mm difference, but enough to not hold the bars securely without the help of a shim.

made a shim out of a can. Worked perfectly.

Thank you!