You're welcome.
You're right, it's 97cc. I wish they always rounded up to the next highest number, but sometimes they really cheat. Several of the 250cc bikes are actually only 223cc.
Just search for "dirt bike air filter", without the engine size. What is important is the OD of the mouth of your carb; mine is 42mm, so that's what I search for. For plastics, either search for Flywing, Pantera, Baja or PW80. You can also just search for "dirt bike plastic", and see if you find a match. You will eventually. You can find a complete set, and use that as an opportunity to change the colour of your bike, if you like.
The o-ring just needs a little oil on it. On the topic of oil, you need to use something compatible with a wet clutch, like four-stroke motorcycle oil. I use Rotella 15W40 from Walmart, which was originally intended for diesel engines. It's perfect for wet clutch bikes.
You can either use a small adjustable wrench or a dedicated spoke wrench on your spokes. I finally bought a spoke wrench from
www.bikebandit.com or
www.rockymountainatvmc.com (can't remember which), and it has interchangeable ends to suit any bike. For me, it was well worth it.
First of all, cheap chains stretch, so expect that. Second, that spacer should likely be between the wheel and frame, not outside of the frame. You can use PW80 chain tension instructions as your guide, which should be easy to find on Youtube.