Haha! I started writing this post this afternoon and didn't see the other similar post. I think this is a little different. I've had an exhaust popping issue for three years and saw something here last week on the ColorTune. I got one and all the cylinders seem OK at idle but one appears to be very rich above idle (2-3,000 rpm) and backfires a lot in that range. I've got the stock airbox with a foam filter and the top of the airbox removed, stock exhaust headers and aftermarket turn-out mufflers that have some baffles. The carb holders are three years old and the exhaust gaskets are the fiber filled copper exhaust gaskets from Z1 that I put on last year. The air recirculation system is gone and sealed six ways from Sunday, and the vacuum tubes are well capped. Most of this doesn't matter since it's only one cylinder (#4) that has the problem. Oh, and I just sync'd the carbs (manometer was still on it when I used the ColorTune).
The pilot jets are two sizes up from stock (42.5 vs 37.5) and the main jets are 125 (vs 120 stock). Is there something I can do to adjust the midrange richness in that one cylinder or is it probably due to a leak?
BTW, the ColorTune is great. Even thought the bike starts and idles well and pulls strongly all the way to redline, one cylinder wasn't even firing at idle. I had to adjust the mixture screw about two turns out to get it to fire right (probably a symptom of some other problem).
1981 KZ1100A1 Shaft
2007 BMW R1200R
