Hi TMNR,
I'm using a 96 Pulsar FN15 X1 as a daily runner for last 4 years & ran 48k so far without major repairs. GA15DE does around 7k on Malabe to Kollupitiya vice versa. But it does around 13-14k on expressway.
Did you check the battery?
I had exactly the same issue with my FN15. I have checked the battery & one cell was not good. I have replaced the battery & didn't had the issue until now. Now almost 4 months