Before I get too far and in order to ward off the flaming, I'm pretty new to 2 strokes. That being said, I'm trying to understand why the popular oil/fuel ratio seems to be around 40:1 when Yamaha calls for 30:1 or 32:1 depending on what year you have. I didn't bother to ask the guy I bought my '00 YZ250 from what he was running because I knew the first thing I was buying was a service manual so at the time it didn't matter to me, but after trolling TT it seems that most people like 40:1 rather then the stock mix ratio. Is this just mainly to get that little bit of extra zip out of the bike, and if so, won't the lack of oil harm the engine? I realize that we are only talking about a minimal amount of oil but, nevertheless, I gotta know whyyyyyyyyyyy!