My dad has a 1996 OR a 1997 KLF300 Bayou. The thing has run well for years, but like most things around our farm, he's never taken it in for service. It's been sputtering and won't stay running very well. He's lost the owner's manuals, which is SO unlike him (note the sarcasm). I'm wanting to change the oil and the plug in it. Does anyone know what weight oil would be best for it, how much oil it needs, what size plug, and any other advice or tips would be appreciated. Thanks.