This is Chicagobob's handy work:
https://www.revzilla.com/motorcycle/...-78-handlebars
Easy way to mark spot for drilling is to remove mounting bolts on 1-piece clamp and lay over triple-clamp. Or do it to paper first, then transfer-punch it. Paper can also be used as template for reinforcement plate underneath. Not strictly necessary, but i've known a couple of stunterz who've broken their triple clamps with bolt-on motocross bars.
Then get any 7/8" bar you want. Genuine FZ09 bars or something similar.
https://www.revzilla.com/motorcycle/...-78-handlebars