Hello, I am having an issue I cannot figure out with the oil in my minibike disappearing. I ran conventional 10w-30 in it, and after probably 3-4 hours of riding with the new oil, enough of it was gone to make the engine shut itself off! I got this engine used, but I have rebuilt it and can confirm there are no leaks anywhere. There is no smoke in the exhaust, and the spark plug looks normal. Anyone have an idea?