This is a short video of rejetting the Mikuni carburetor on my DR650 with a Six Sigma jet kit that I got on eBay. They include personalized instructions that were fairly easy to follow and several jet sizes for different progressive stages and altitudes. This video shows settings recommended for Houston w/airbox mod, stock muffler, and mild performance increase (small hole drilled in slide, but did not clip the spring. EDIT: You can also call you local dealership and ask them what settings they would use. They usually sell the jets and you can pick up the spacers at Lowe's. I do recommend the extended fuel mixture screw from ProCycle.