There should be no side-to-side play, but you certainly don't need to torque them down that much. Put the bike on a rear stand, and the weight of the Busa will be enough to hold the the bolt from spinning. Get a 17mm wrench and tighten down both top and bottom bolts. That should be it. Bolts shouldn't be coming loose.
Now these are dog bone links, right? Not the adjustable kind which can be prone to breaking or getting out of adjustment.