Hi, what do you call these weights in English? In German, they are called ‘Lenkergewicht’ or ‘Lenkerendgewicht’ and they are used to reduce vibrations of the handlebar of a motorcycle. Interestingly enough, so far there is a Wikipedia entry on handlebar weights in German but not in any other language. Seems, the Germans are more fond of technical topics and mechanical questions than other nations.
I’m no longer a rider, but I found this item on the US Amazon page:
“Kuryakyn 6339 Motorcycle Handlebar Accessory: Hand Grip End Cap Weight, Gloss Black, 1 Pair“
The weight appears to be 14.9 ounces for the pair (possibly shipping weight)
Another term is “Handlebar Grips Plugs”, but often with very low weight.