I was fighting a bog and found out I had destroyed or lost the O-ring on the fuel screw. Weeks of work and it turned out to be something dumb like a 1 MM (if that ) O ring. If you work on bikes or cars, you spend 1/2 your time on the repair and 1/2 the time on 2 or three lost bolts or torn gaskets or 1 or 2 parts you have to order and wait on. I called Boysen and they asked me to check it because so many guys lose them. My hats off to Dag and Ed at Boysen. These great guys are happy to talk at length about jetting and maintenance with callers. They know what the trends are. Ed is going to send me some pictures of how to put a leak jet in my YZ. From his description, it sounds like the way to go. I will post it later. Good luck and good rides.