HI. here is a frequently question. How often should I change the engine oil? WR 450 2008. The manual says for competition use every 1000km and the maintenance for the emmision control says every 2000km Which is right? I have motard rims 17' and 42 rear sproket. I ride the bike about 4 times a week doing some wheelies and riding around (about 30km per day) and sometimes (weekends) i ride about 120km. Total 2000km every 3 months. The temperature ranges here are from 20 to 35 celsius.