1978 yamaha DT 175 oil injection?

I've been tinkering with my 78' yamaha dt175 and have come around to the oil injection system. Looks like the previous owener removed the oil tank and lines and was running premix, but was warned by a crusty veteran at my local shop of the dangers of deleting oil injection systems with these older bike because on some the system would supply oil to certain parts of the enguine that wouldnt get any oil if you were to just run mix thus resulting In blowing your engine up in one ride. Seeing that he rode it as is and its not a block of fused metal I'm assuming its okay? But certainly wanted to double check befoer causing any further damage. If anyone has any input on this subject that would be greatly appreciated!
I had a 71 Yamaha HS1 90 and the oil injection on it dripped oil into the intake between the carb and the cylinder; nothing else. The gearbox had it’s own oil. Most 2 stokes get the lubrication for the piston, rod, and crank bearings from the oil in the gas.