Shifter moves on big bear 350 but quad wont reverse now it goes forwards

It's designed to only start in neutral. If the reverse light is on, it will not start with the button.

The wiring needs to be reversed.

Isnt this an automatic trans? Does it have a shifter by your foot,or at your hands? If its at your hands,then it could be that its just idling too high,and needs to be lowered. If it isnt auto,and has a clutch lever,try adjusting the clutch at the lever.

check the shifter switch under the dash and disconnect and reconnect just to make sure there is good connectivity

remove the battery and the black plasctic piece this will give you access to the shifter switch, verify that the connecters on the bottom of the shifter witch are still connected

it sounds like the shift linkage came off the shifter, pull the shifter boot up and you should be able to get to the linkage

Try lubing the linkage where it shifts from forward and to reverse the linkage is most likely freezing up or has snow or ice build up causing it not to shift, My thought is your shoving it hard enough that it finally engages when you get the snow or ice to break off.

Sinccronise the gearbox and then try again.

left and push the shifter into the floor like stabbing down ten it will go left a little more and push forward and you will be on your way in good ol R

Sounds like the car is just slipping out of gear. Keep your hand on the shifter when you back up next time. See if you can feel the shifter move when the car comes out of gear. If the shifter moves up when it happens keep pressure on the shifter holding it back like you dont want it to move forward. And of course if the shifter moves back when it comes out of gear, put forward pressure on the shifter so it doesnt slip out. This might work for now but but i know i wouldnt want to spen 700 for that ****. Let me know how it goes.