Yep. Your TTR was a trail bike 4 stroke. That's nothing like an MX 4 stroke.
MX 4 strokes are essentially a little Formula 1 motor. They have tons of HP and torque, but they can't compete with a 2 stroke on an equal displacement comparison - and the 4 strokes are a $2000.00 blown motor waiting to happen - especially the 250 4 strokes.