I have a 06 yz450f and it has 15.6 hours on it I've used yamalube 4R every since I bought it new in December 2006. I have rode it now for 3 months, today is march 9th 2007 and I was wondering if I should keep useing yamalube 4R and changing it after every practice day at the races and changing it after every race. "What Iam saying is" we just started racing season this past weekend 03-05-07. I practice on saturdays at the track after practice I change the oil. Sunday is race day I run two classes and at the end of the day after the races or before I ride it again I change the oil again and clean the ready racing oil filter. Now what Iam getting at is am I changeing to much or can I slack up a bit. Before you reply remember I am racing it this year about 3 or 4 weekends a month and Iam useing yamalube 4R. Please help me decide!