Just bought a 2001 250 Trailblazer. No owners manual, how many quarts of oil and is it ok to use other brands other than Polaris?

 

You can use any good brand of 2-stroke injector oil in it. I had the same quad except it was a 2000, and after I used up the Polaris oil I bought some smokeless 2-stroke oil but can't remember what brand. I don't know how much oil it holds either but IIRC it should be enough for 2 tanks of gas. But don't hold me to that. Pick a brand and don't switch back and forth, back and forth between brands because some of them can get gummy when they're mixed together, or so I was told.