Hi Guys, I noticed some popping on decel ever since I had my upgrade to 1200 done. The techs at my dealership were not familiar with the Dobeck TFi and I don't think they changed the settings so I set to the numbers Chris at Dobeck suggested. I still get quite a lot of popping and now I notice a thick coating of pure black soot inside my mufflers. She accels well and fuel economy is about 38 miles to US Gallon. I felt a bit uneasy reading Glider's comments about carboning things up inside the engine and fuel diluting oil when the mix is long term wrong........:34: In a post on 11th April, our good friend Bubbie made the very helpful suggestion as follows: QUOTE: YES, alter to work properly on your bike... If still popping when letting off I would open TFI up a bit more and try: on the #1 first IDLE pot= +1........ and the 3rd pot one = + one mark... give that a whirl. you might even need 2 marks up on pot 3... settings by dobecks are just suggested and your bike may need more gas than the TFI is giving... The beauty of TFI, it is easy to go back n forth as needed.. signed....BUBBIE :UNQUOTE Now I have not done this yet before my last minute mad dash to Ireland last Tuesday and because I want to be clear in my head on what is happening between popping and soot - does the same fuel/air ratio fix both? Are they different symptoms of different problems requiring different solutions? Excuse my ignorance but is popping due to too lean or too rich and same question for soot? Can anyone suggest some settings for the TFi in this situation? 2009 Sportster XL883 converted to 1200, SEII pipes and K&N million mile AC. Thanks for your help guys/girls. I'd like to sort it out before I ride back home to England on Weds.