Solution manuals for standard textbooks like Khurmi's are (usually published by S. Chand & Co.). They are not officially available for free download. Many PDFs circulating online are unofficial, scanned, or incomplete . Installing/unzipping such files from unknown sites carries virus/malware risks.
While a single official download link from the publisher is rarely available for free, you can find significant portions of the solutions on these platforms: SlideShare
Master Theory of Machines not by possessing the PDF, but by understanding the 5, 10, or 50 problems inside it. Good luck with your mechanisms and machines.