Stuck throttle after the bike was knocked over

My 1980 KZ750E was knocked over in a hit-and-run last week. It fell on the right side and did little cosmetic damage. The handlebar is bent upward. Most bizarre, the throttle grip will roll back toward me (accelerating) fine, but something is keeping it from snapping back on its own (yep, this is a safety issue). It's as if it has a constant built-in cruise control--it must be manually put back to idle speed, or anywhere in between for that matter. I pulled the grip off and it moves on the bar just fine. I'm looking for other flaws/damage, but have come up empty thus far. Has this happened to anyone? Any ideas from experience where to look next? Thanks.

I haven't had this happen but here's a few ideas to check.

Kinked throttle cable - does the cable move freely in its sheath

Throttle housing - is it damaged, does it bind the throttle tube

Broken throttle spring (on carbs) - does it make the throttles close.

Broken wire(s) in the thottle cable - will bind cable intermitanty(I've had this happen with my clutch, but only when the handle bars were turned to the left and then only sometimes:pinch:)

A wild guess is that the cable has been bent/crushed a bit and binds when the whole thing is assembled.

Looks like a new throttle cable is in your near future.