If you need to compress the swingarm to get the bolt out, try hooking a ratchet strap between the grab bar and swingarm.
Ratchet the teeth one at a time until the bolt has no more tension, remove bolt.
If it's on a floor jack instead of a stand, sometimes all you need to do is keep the tires on it, then adjust the jack until the weight of the quad on the swingarm takes all the pressure off the bolt.
If the weight of the quad by itself is not enough for some reason, honey can sit on the seat without breaking any nails 
Once the bolt is removed, you can jack it back up or put it on a stand to finish disassembly.