ytman· used ta could
I recall seeing the mounting tabs broken on some Free Spirits units so that's something to look out for. I definitely would not attach it to the tank. The difference between the movement of the motor and that of the tank would destroy it. The rubber between the throttle body and the airbox on the XR is like a big speaker cone with lots of flex. I'd make a bracket to carry the filter off the motor also. That's just me tho.