WR 450 Oil Change, When and What?

I haven't changed the oil on my fancy new WR 450 Yamaha yet. It looked good so I just went for a ride. I have been researching the ever debated oil change issues. I read that with a brand new bike 35 miles is plenty for a break-in oil change. I guess I can agree with this, but the intervals seem really, really small for an oil change. A car goes 5,000 miles and my Dodge truck goes 10,000-15,000 miles. I guess the difference is the amount of oil in the tank.

Most people mentioned that after every 10 hours of "normal" riding It's a good time to change the oil. The recommendations are to get an hour meter which aren't expensive ($40), so then I guess you take the guess work out of how long/far you ride. I have the electronics on the bike, but I am not sure how it really works and if it has an hour meter.

Do I use Motul 5100 10W40, Amsoil 10w40 motorcycle oil, 10W40 normal oil, or mobile One 20w50 for the hot summer? I have been a fan of Pennzoil over the years, but I do like Amsoil. I am not sure what to get, or how to change it.

Another good maintenance tip is to clean the air filter often. I will agree that the most important things to these bikes is clean air and fresh oil.