Originally Posted by
strngdze
Eagerly awaiting for the correct answer on this one...I've always wondered why that was there. The button seems perfectly symmetrical??
I too am looking forward to the correct answer, but I think it probably has something to do with directing the in coming charge or some junk like that. Either that or because the head is fitted to the sleeve according to gaps, and that indicates where the exhuast should be for best seal?