Bahahaha! I'm laughing at the thought of someone lifting one of those chains. You might need to upgrade your suspension before laying one of those over your quad. And maybe a winch to pick up the chain. Hahaha
Do you have to keep your quad outside in the open? If so, try using a winch and pull the quad up in the air over a big ass tree branch. If it keeps bears from getting food, it should work from keeping theives from getting your quad.
I had to cut one of those Kryptonite locks at work and I thought I was going to pass out. I managed to get it, but that thing put up a fight!