The sound you're hearing, described as "khut," when applying the 1st or 2nd gear in your Pulsar 150 motorcycle could be indicative of a mechanical issue. Several possible causes may be contributing to this noise:
Clutch Issues: It's possible that the clutch plates are worn out or improperly adjusted, causing them to slip or not engage smoothly when you shift gears. This can result in a grinding or knocking sound.
Gear Synchronization: The gears in your motorcycle's transmission system need to be synchronized properly for smooth gear changes. If the synchronization is off, it can lead to a noise when shifting gears, especially when engaging 1st or 2nd gear.
Gearbox Problems: There might be an issue with the gearbox itself, such as worn-out gears, bearings, or other components. Over time, these parts can wear down and cause noise during gear changes.
Chain and Sprocket Wear: A loose or worn-out chain and sprocket can create irregularities and cause noise when shifting gears. It's important to regularly inspect and maintain your chain and sprocket to prevent such issues.
To pinpoint the exact cause of the "khut" sound in your Pulsar 150, it's recommended to take your motorcycle to a qualified mechanic or service center. They will be able to perform a thorough inspection and diagnose the problem accurately. It's important to address any mechanical issues promptly to prevent further damage and ensure safe riding conditions.