I agree, this vent system is the best on any saw. I love it. Here is the problem.
When the saw is mounted in an ATV chainsaw carrier with the bar pointing directly down (I know this is bad for the saw), fuel leaks right out this vent. This vent system just isn't meant to be transported in that position. If I had some other type of vent, I might be able to carry the saw without leakage.