fairweather

Hi i am restoring an rd 50 mx for my son and need a new regulator ,does anybody know where i can get one!

I've got an xt350 which miss fires or jumps roughly between 6 and 8 thousand revs ,worse when hot .i`ve cleaned and checked the carb and seems to be fine ,fitted a new plug cap and new coil still no change .Running out of ideas can anyone help. When you let the throttle off a bit it runs sweet.