The actuating rod usually breaks. The reason it does usually break is due to non-support of the shaft during disassy/reassy.
I realize yours is not a 'H' model. Still, a '90 parts diagram shows a nut on the top of the shaft. In the 'H' model, this is a LHT nut. Point of that is that it often is tightened when it's meant to be loosened. Even when turned the correct direction, the shaft must be supported when wrenching the nut.
There is a governor shaft lever on the bottom of the actuator shaft that is held on with fasteners. It may be loose.
In any case, I'd suggest you don't ride the bike...don't even kick it over until you get the problem resolved.
Little pieces may well by lying around inside the RH cover just waiting to grenade your motor.
.......it's happened before!!