I have a 02' zr 600 Cross Country EFI with 700 miles on original plugs. Sled started to backfire and bog, but it would also surge the rpms too when I was braking. Stopped and changed plugs (plugs had black residue on but the tips were brown. Started fine and rode another 100+ miles before it started doing the same. Again, changed plugs which looked clean and tan and was good to go again. When I got to the hotel sled was idling at 4K when I stopped and gradually backed off to normal when I stopped about 10+ seconds later... Any ideas? I really appreciate it!!!