I have a 71 Honda SL70 that I have owned for 33 years, since I was 14. It runs great but recently it developed a transmission problem. The splines on the kick starter shaft stripped off years ago so we just push start the bike. Without any warning or indication of a problem, I went to start the bike, I pulled in the clutch, put it in gear, started coasting down the driveway and when I released the clutch nothing happened, the bike freewheels. I can feel that there is a little increase in drag and it sounds like something in the tranny is turning but the piston is not moving. Removing the flywheel cover, I can turn the flywheel and the piston moves. Any ideas? Thanks in advance for your help.