There are alot of opions about the park brake worth a crap. I have had good luck with mine. I have a 06 650 XT. The key is to keep it adjusted. There is some adjust ment that can be made at the rear caliper with the cable linkage. If it is adjusted all the way you will have to take the arm off the caliper and reclock it. Your pads also may need to be replaced. What year 700 XTX?
Ok it is just like mine. For be excess lower the back half of your bottom skid plate. From under the machine you will have a good view of the park brake calbe attaching to the caliper arm. Loosen the adjustment jam nut and get all the slack out of it. Take the nut attaching the arm to the caliper and then the take the cable off the arm. You will need a small two jaw puller to get this arm off. Take the arm off and reclock it on the cam. This will take up the shoe wear, then you can put the cable back on. You know you have it right when the cable adjustment is as loose as it gets and the pads are almost touching the rotor, this will make the pads contact with one or two clicks on the pedal. Hope this helps.