I had the same problem. You must have pulled the cover off with the chain guard on lock position. Thats the front hand guard. What you need to do is fit the round part on the cover that has a little gear over round part of the front guard handle. Its okay if the round metal band doesnt fit over the flywheel at this point. Dont worry about putting on the 2 bolts yet. Next hold the plastic cover down hard and make sure it pushed into the round gear on the front hand guard, it will be angled a little dont worry, next pull back the kickback handle and that will engage the spring inside and force it back into the unlock position and this should expand the metal band so it will fit over the clutch. I finally figured it out by taking off the cover and unscrewing the face plate on the spring. I saw the configuration and knew that I had to use the hand guard to release that mechanisim to expand the metal band.
Kurt
May 2005
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix chainsaws.