can-o-worms.... urg, not another one.... Let me see how efficiently I can get through this...
Right, There is no such thing as "the best oil".... Run Kawi 10w-40 if you'll change the oil AT LEAST every 3,000 miles.... I change mine every 2K. If you go with anything else synthetic, semi-synthetic, it's best to contact the manufacturer asking them which intervals to change it at, what kind of wear and tear you can expect.
Some automotive oils have extra additives in it which aren't terribly good for the wet-clutch which is bathed in the same oil as the crank-case/engine oil, on the 250R. Thus, be careful which oils you buy for your bike. How will you know? It will have a "JASO" emblem somewhere on the container which means the Japanese moto manufacturers have tested it and certified that it will work well in their motos.
Also, don't buy expensive oil, like Royal Purple, and plan on changing it every 2K miles... It's just taxing on the environment, and totally not necessary.... If you run Royal Purple, plan on at least 6K between oil changes. This might be an option when covering a lot of ground in a season, but it's worse for you engine to have oil sit over a "winterized" season. Heat cycles and temperature differences are what kill oil. So, to me, it makes sense then to change the oil more often than to press the more synthetic oils further.... The reason I use Regular old dyno juice like Kawi oil is because it breaks down quickly, so I can change it often, which means I get a look inside my engine every 2K miles by "reading" the oil.
