Take it easy brother it wont cause any harm, I have P180 2005 model, when i bought the bike in kolkata, we could only get Power1 15W40 or Activ 20W40, I used it for a while then switched to castrol GTX 20W50 as per Bajaj mechanics meant for cars, Thank God Castrol is selling 20W50 Activ 4T now, which i use now, you can buy that and even get the engine oil changed by a local mechanic, it just takes 5 mis, and dont worry there wont be any chemical locha , 20W50 is used because it can handle higher engine heat generated by the 180cc engine, you can go through the engine oil thread to get more info

Changed oil to Motul 3000T Plus 15W50 is it good?

Mineral Oil is recommended for new bikes.anyways...

As Pulsar 150 company recommended oil speci is 20w40 and for Pulsar 180-200-220 company recommendation is 20w50 oils
w40 or w50 means the thickness of the oil if you use w40 oil in your bike then the oil will not stick to the walls of the engine or cant give proper protection.
using 15w40 oil instead of 20w40 engine oil in pulsar 150cc means flowing of engine oil in engine is much easier as compared to 20w40 recommendation. Using wrong grade of engine oil results in a hard to operate clutch,notchy gearbox and internal engine damage.So the rating in starting could be change like 10w50 or 15w50 or any thing but remember don't forget the w50 rating should be there as constant.

1>Shell Advance SX 4 15W-50 Motorcycle 4 Stroke engine oil TRY THIS....
2>BPCL Mak 4T 20W50
3>Valvoline Premium 4T 20W50
4>Elf Sporti 20W50
5>Motul 3000 20w50 4T
6>Motul 7100 20W50 4T

Engine is getting very hot even after a 10 min ride i have done 55 kms changed oil to Motul 3000T 15W50 Engine still getting very hot! and the red over rev indicator on the rpm turns on anytime even if i havent touched 5000rpm i can feel the heat as soon as the bike stops near my legs even from a jeans pant it gets very hot! any reason? i will got to the bajaj guys tomorrow

Means that you have done only 55kms on your new bike or oil changed.Total odo reading is 55km