The TT250 has a very basic chain adjustment system, not much different from other bikes....except for the rear plate. I noticed that the plate on mine had rotated about 90 degrees after a brisk ride. Maybe I did not torque it down enough...not sure. The plate is pretty flimsy. With some scrap aluminum and a mill I made plates that won't slip:
notice how thin the OEM part is...and no lip to hold it in place
installed.
Peter Y.