Black oil?

I didnt notice those were rubber gaskets.....my local parts store sells rubber felpro gaskets but they are bright blue.....anyhow,thats your problem right there! lol......with only 2,000 miles on the engine......its still breaking in! you just need to wait it out...it will get cleaner as more miles and oil changes are put on it. its just now letting the pistons cut a groove into the cylinders and all your bearings are wearing into the rotating assembly,not to mention if you used assembly lube (wich you should have during a build!!!) that stuff will keep your oil dark for a few oil changes worth. anyhow,I don't think you have anything to worry about,just make sure your carbs tuned in good and that your ignition system and timing are all up to par.