I have a 455 rancher, it's about six months old, great saw, but it keeps spitting the chain. when it spits the chain the drivers get dinged and i have to file them so they fit in the bar again. What am I doing wrong? is there something obvious tha I am missing. I ran my jonsered 2054 for years and i don't think it spit the chain once. Any help would be greatly appreciated.