I am currently trying to fix up a 89 Yamaha Big Bear 350 for my wife to use (2nd machine).

This is one has the shift handle on the left side with a thumb lock (or release) button in the handle (knob).
The problem I am having is that it's missing the button and I am unable to get it to unlock to shift it into reverse when needed.
And I haven't been able to find parts the shifter.

Is there a way to bypass this so I don't have to use the release button?