I recently bought a used 05 Ninja 500R. It had 1100 miles on it when I got it, everything works perfectly still and I'm now at ~2600 miles. Should I change the oil already, and if so, what brand of oil, how much and what viscosity? Also,should I replace the filter as well?

Does the above mentioned process (oil sight on the side of engine, fill/drain plug) work for my year as well?

Thanks in advance for answering the noob questions, I'm familiar with cars but this is my first bike.