Very confusing topic I want to know exact drain interval of engine oil company says 6000 km and my mechanic says every 2000 . I use semi synthetic veedol take off 4t 10w30 api sn in my hero honda CBZ xtreme (2014) . If I switch to 10w40 will be any issues please help me out . Please answer
You have the recommended interval from your mechanic and the recommended interval from the oil manufacturer. But you are missing the number that you should start with - the one from vehicle manufacturer. If your vehicle came with a user manual, it's generally in the preventive maintenance section in that manual; if you don't have the manual, look online for your make & model.
Oil change intervals frequently specify both distance and time (e.g., "every 3000 miles or 3 months, whichever comes first"). 2000 kilometers is on the low side, but if you don't drive long distances, it may be an appropriate interval.