We ran 40 mm belt drives for a long time on TaG engines and they weren’t reliable enough, for us, so we went back to 219 chain. The chain was more reliable but came with it’s own problems. Used high quality gears, lub and chain and laser aligned the gears. But some tracks were just murder on the chain. Practice sessions were OK, but after a 25 minute race, the chain was bone dry. So dry on occasion, the chain was not only dry but turning blue and stiff. Oh, ours was a non-O-ring chain. If we had continued for another season in road racing, we would have had an oiler.
Scott Grenier put an oiler on a Rotax and I saw the results. His chain was fine and I was tossing mine out. And there is a cost factor. Spray cans of chain lub are not cheap. But chain saw bar oil is.
The issues with installing an oiler is position so the oil drips on the chain and the drip rate. So a little experimentation is required.