Missed your bad fuel consumption.

I have done worse, by having fun on gravel.

Agree, it should be much lighter on fuel, although I never checked fuel economy on the DRs I had.

The DR's carb is quite simple. Take your time when taking it apart, and note where everything goes. When you remove the float bowl screws do it with a JIS star point. Japan Industry Standard. You can replace with Alan cap screws.
As was said already, check your carb is stock ito jets, and needle position.
You might have a too big main jet, or lifted needle. Back yard "tuner"!
MotoComp in Kzn stock the jets.
With a stock carb and clean/oiled filter you should be close to a good running DR.
Do you still have the stock exhaust?
For peace of mind check spark plug condition and valve clearances.
Shout if you need help!
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