The shifter keeps sticking BAD on my 04 600-twin. It only happens when it's cold. I've got to the point where, when I trailer it, I just leave the ATV running on the trailer so it keeps the motor warm enough, and will allow me to shift the thing when I get there. However, it's not ideal, and not always practical. AND, it doesn't always work. I went and did some plowing last night and when I trailered it home, I left it running but it still wouldn't shift into Reverse when I tried to back it off the trailer.

Sometimes I can shift it by putting a pair of vice grips on the little arm that connects to the shifter input shaft, but sometimes it's frozen up so bad I can't even move it. There's been too many times I've had to somehow drag a 1000 pound atv into my garage and blast a heater on it.

What causes this and how do I fix it?

 

Clutch's could be mis-aligned, idle could be to high, broken motor mount, water in the shifter housing causing gear's to bind up. Check these thing's good luck

 

How does it shift when the motor isn't running?

John

 

the shifter linkage is tricky to adjust, and terrible to get in gear, if the adjustment is not correct.
Follow the steps in your manual, until you get it right.