Given many 125cc bikes use just 1 litre of oil, it might be getting a hard life with a fairly high revving engine. On My Grandsons Yamaha, i used the highest quality synthetic oil at about 14 pound a litre due to his lack of any bike knowledge. I used to oil change it every time he turned up at my house. There is a very crude oil filter on those 125s. In 10000 miles he neglected it, at least the engine was still vey quiet with no faults.
I think high quality oil would be a good recipe on a small 125 capable of near 60 mph