I just bought a 2004 Predator 90 (our first atv) that my son will be riding, and I'm ready to perform some maintenance/upgrades this winter in an attempt to make this atv as reliable as possible come spring. I don't need it to go any faster, just run! The original owner said that all he replaced was plugs, batteries and light bulbs. Everything works, it just runs a little sluggish so I know the carb needs cleaning (old gas). My question is...what other parts should I consider replacing while I have the unit torn apart? I'd rather replace old parts now than when we're on the trails. Thanks!