Last summer I changed the oil and oil filter in my 2001 Honda XR250R dirtbike. The oil I used was Shell Rotella T 15w-40 non-synthetic. The oil filter I used was "Tusk First Line Oil Filter". Based on the reviews I read this was a good combination for my application. Since then, I road around 80 miles or so. This is off-road riding meaning high revs and lots of clutch use. The riding season is starting to open up here and I want to make sure I'm doing the right thing for my bike. My question is...is it ok to keep the same oil and oil filter in my bike for this riding season? The bike has been sitting since October until now (not ran since). Or should I just change the oil and keep the filter in there? Or should I be on the safe side and change both the oil and oil filter?