Bro as per my understanding, you are saying that the oil level is half the total capacity after 5000 KM. The oil capacity is 3.1 liters so 1.55 liter every 5000 KM for a small engine is very high.
It is true that some oil is burnt during combustion, but still there is a limit to this. You may use a thicker oil but this issue has to be fixed. An engine compression test is required to evaluate the sealing of the piston oil rings and cylinder head valve seals.