If the compression is good, the valves are probably ok. Spray just a little starter fluid in the intake and see if it starts. If it does the problem may be fuel related. If it doesn't start, it may be ignition. On a old bike, it is a good idea to remove the seat and tank and disconnect and clean all of the electrical connections you can. Use some electrical contact cleaner.
1985 Kawasaki ZN700 Shaft, 4cyl
1989 Yamaha Venture Royale
2007 Yamaha Royal Star Venture