I have a 2000 YZ 426F that I let my buddy ride the other day. As he slowly rode off, I noticed dust kicking up from the ground directly underneath the foot pegs. Upon closer inspection, I observed that when the bike is running, exhaust gas flows through the rubber tube -- the tube that acts as an exhaust tube for the compression relase valve. Now, I understand that gas should come out of this tube when the compression release lever is pulled and the kick start is kicked, but should it happen when the bike is runnning? Is the compression release valve one of the two exhaust valves or is it a dedicated valve?