There is a hose linking the air box to the lower half of your engine for positive crankcase ventilation. And when a kfx gets upset or stood up on the wheelie bar the oil from the bottom end runs into your air box. I believe the manual instructs the oil to be checked through the side looking glass while its stood up on the wheelie bar and any extra oil over just being full goes into the air box. It holds 1.25qt of oil and its smart to drain it and then measure the exact amount rather than to stand it up on the bar to check it. However look at the oil in the looking glass on the bottom end and you will see the oil color...if its grey there then u have other issues. But if its normal then the grey oil in your box just mixed with water another way....meaning u should be fine. I disconnected mine and installed a filter from a valve pan cover and mounted it up higher to prevent that messy little accident from happening when i wreck.
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