The Bajaj Pulsar 150 2016 model typically comes with a stock rear tyre size of 100/90-17. Installing a 140 size rear tyre on a motorcycle designed for a narrower tyre may not be recommended as it can have adverse effects on the bike's handling and performance.
Using a wider tyre can affect the bike's stability, especially during cornering, and may result in reduced grip on the road surface. It can also impact the overall gearing and speedometer accuracy of the motorcycle. Moreover, installing a larger tyre may require modifications to the swingarm, fender, and other components to accommodate the wider size.
It's generally advisable to stick to the recommended tyre size specified by the manufacturer to ensure optimal performance, safety, and compatibility with the motorcycle. If you are looking to modify your bike's appearance or improve its performance, it's better to consult with a trusted mechanic or contact the manufacturer for recommendations on compatible tyre upgrades for your specific model.