Every 3,000mi (5,000km) is the safest choice. Certain conditions will require more or less frequent changes, but with that interval you can't really go wrong.
10w40 but it should be approved for wet clutches.
Check the oil cap and the drain plug, as well as the oil filter.
ex250 ninja 2008 10w fork oil, 360 ml and 108 mm air gap
its not really picky but I'd go for 5w40
10 qts should put you in the middle of the checks
You should buy probably buy 5w40 this is the most commonly used oil for motorcycles but realisticly the 250 is not picky and anything will work. the one thing to make sure you dont buy energy conserving oil, I guess its not good for the clutch. http://faq.ninja250.org/wiki/Engine_Oil
After your first 250 miles, and every 600-800 miles after that.
300cc from Mobile Cycles in san diego, CA
it says 1.9 liters on the side, that's about 2 quarts.
588ml dry or ca 500ml oil change
2200 ml
We're is oil Filter on a Honda trx 250 farm quad 2001