The recommended engine oil for your Bajaj Pulsar 180cc may vary depending on the specific model and year. It's important to consult the owner's manual or manufacturer's guidelines for the correct engine oil specifications.
That being said, the Bajaj Pulsar 180cc typically requires a 10W-30 or 10W-40 engine oil. Using a 20W-40 multigrade oil, such as MAK multigrade 20W-40, should generally be acceptable for your motorcycle. The "20W" indicates the oil's viscosity at cold temperatures, while the "40" represents the oil's viscosity at operating temperatures.
If you're uncertain about the appropriate engine oil for your specific Bajaj Pulsar 180cc model, it's best to contact a Bajaj authorized service center or consult the owner's manual for the correct oil specifications.