I've been attempting to tune my 750K3 for pods (I know, I know, but I don't have the stock airbox, and it's a cafe build). The bike also has 4-1 with a cherry bomb muffler and a small ineffective baffle. The system is probably about as open as it gets.
Obviously I've been dealing with a lean condition and I've made some gradual changes to get it closer to normal. I've recalibrated to 26mm float height, rejetted the mains to #123, dropped the clip position from default position 4 to position 5 (bottom). I have a set of #42 slow jets on order. The air screws are about one turn out. These are 657a carbs.
My question: my last change was to drop the needle clip position (raise needle), and I also changed the air screws to about one turn out (I had mistakenly set them at two turns out initially). Following a ride of about 15 miles I pulled the plugs and found that number 1 was pretty sooty, whereas the other three looked pretty lean (fairly consistent among the three). What is the likely cause of 1 cylinder looking much darker than the rest? Should I start with the air screws? Or is it likely that I messed something up while dropping the needle clip position?
Until yesterday, all four plugs were looking consistently lean, as expected.
See photos below contrasting cylinder cylinders 1 and 2.
Thanks,
Aaron
Sent from my iPad using Tapatalk HD