Only 2-stroke bikes can be deristricted. 4 stroke 125´s are unpowerful because they have pistons the size of 10p´s. 2 strokes make up for this by revving like %!¤es. 4 strokes will go further per gallon though, and 2 strokes need a new piston and sleeve every now and then (90 squid for a DT125.)