I figured i would chime in on this since I just done this on my Kodiak 450. Grab pull rope starter and pull on it, if starter spins while pulling rope, then one-way bearing is locked up. You will need to check gear wear on starter, idler gear, flywheel, and check all parts that are used to start bike. The job is pretty simple, just expensive if you buy all new parts. I found part at local atv repair shop and he even let me use flywheel puller to get my broken one off. I paid $50 for a used one-way bearing and new it costs $94 w/o shipping costs, prolly the same price for grizzly. just to give you an idea of what you will pay, www.partforyamaha.com
, they are a little high but it will give you an idea. don't order from them unless you don't have a local dealer, b/c they do the same as dealer, order, wait, then ship to you, 3 week turn around. If you need help with the grizzly pm me and I will do all I can to help. I done mine about 2 months ago and it is still fresh in my mind. Don't forget to check keyway after pulling flywheel to make sure it hasn't got any wear on it also, mine was almost sheared.