I have a 06 yamaha 450f with 74.3 hours on it now. I have just done one topend on it since i bought it new and it was done at 50 hours. Nothing was wore and the valves didnt need much adjustment. I will go to about 120 hours before i do the top again. My question is? I use amsoil mcf 10-40 and change it after every race weekend (2 classes-4 mottos) plus a few laps of practices that morning. I just want a cheaper oil that is easier to get. Since I change the amsoil after every race I might as well switch to a cheaper oil. Which Rotella oil is best used for racing that I could change after every race weekend.