Does it have bar risers? If it does the cable could be pulled so that there is no slack, and when you close the hood, it pulls the cable slightly, then pulling the slides on your carbs slightly. Happened on my sled.
It may have slack but I would guess it's getting pinched at the junction of the hood and steering column, or on top of the airbox. Even though there may be slack, pressure on the cable can make it do what you are describing.
Take the throttle cable off the throttle block and see if that makes a difference. Tape down the safety switch in the throttle block if that is still working.
Reroute the cable if needed.
PS--I ain't at Haydays! And it's only an hour away from me!
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