A lot of kx 250 do this ,check all plates for wear and flatness ,check springs for length ,you could go to stiffer springs as well, you could try some of the after market company for a new basket if it grooved out real bad as they use better material etc.How many hours has it done ,the bearing under the basket should be replaced if you change the basket,i pushed a kx250 to 230hours before things started to go wrong than fully rebuilt the lot,the plates will break if things wear to much so preventive maintenance is your friend.
