Thanks Graeme. Yes, that is the plan -empahsis on plan at this stage.
The background for this (potential) project goes back to her first bike. A DT175 (mid-late 80's - not my first preference r.e: design). She had the DT for awhile before getting into DR's. She fondly reflects on the DT, it's low seat height & hence ease of maneuverability. The DR250 was apparently always more awkward, being taller and only allowing one lot of toes to be touching the ground meant it was less fun in the real world. The DT's issues lay with it being underpowered, lacking suspension travel and having awful brakes.
We're both currently dirt bike-less And as most people get older & wiser. We've somehow become older, faster and more stuborn (both into fast road bikes, cars and so on).
I've not long become a regular reader of VMX quaterly and love the classic, big 4 stroke engines (never liked 2 strokes, after owning a tempermental IT) in low production/custom frames.
Which leads me to here, and wondering what's involved in a DT thumper conversion.