I just bought a brand new '05 CRF450. So far its love. I put 2 hours on it and just changed the oil today. I was wondering if anyone out there has advice on how often to change the oil? I have been getting conflicting advice from people on how often to change the oil in the transmission and in the engine. The manual says nothing. Also, has anyone bought stainless steel oil filters. I had some for my last bike (a KTM 450) and they worked great. Would like to know if there are any recomendations for who to buy them from. Thanks.