After removing some dents in my pipe and repositioning rubber mounts to get rid of vibration on gas tank I took my bike for a quick test run...accidently running bike without the baffle/spark arrester/packing material. What a difference in overall power and responsiveness. I then checked the sparkplug and found the bike to be running lean. After playing with the jetting for some time, taking aggressive rides and then rechecking the sparkplug I found the perfect jetting combination..Main jet moved two notches down towards the rich settings. At this setting, a brand new spark plug was golden brown throughout. Why not run the bike this way all the time? Is there any long term problem? In the woods I would have to put the spark arrester back on and rejet.