If the diameter of your handlebars is too big for your bell, you can use this adapter to mount the bell.
I recommend printing it with PETG. I used Nobufil PETG Alu Grey.
You can use M3 x 3.0 threaded inserts and a M3 screw, but my handlebar fits so well I don't need them.
The author marked this model as their own original creation.