I recently bought an Athena 478cc bigbore for my 03 yz450f and after reading through the instructions to it, they recommend a new piston after 15 hours! I usually tend to believe the manufacturer on their own specs, but is this realistic? I was hoping for maybe more like 50-60hrs, is this because it is a 2 ring piston setup? maybe fixed by a 3 ring piston? also they specify 96 octane.. what are your thoughts on this?