OK, I put the 128 back in and left the pilot air screw at 2 turns out and left the dynojet needle in on the 2nd slot from the base. I rode 145 miles this afternoon, mostly on gravel road at 40-60mph with some paved roads at 60-70mph. I got on it pretty hard exiting corners but otherwise rode a constant speed. I averaged 61mpg using 91 Octane premium. I still might try a 126, especially when it warms up this summer, I expect it to richen up a little, but for now it's fine. I think the popping is unavoidable and probably mostly a result of the dynojet needle and the larger hole in the slide.

 

Nice, thanks for the report. I also pulled my needle today and moved it from the 3 slot from base to the 1st slot. It felt better all around but the popping is still there deacelerating at about 5-4,000 rpms. So with the e-clip in the 1st slot I should be saving myself a little bit of gas.

 

I had the same problem with popping on deceleration. I've got a FSW full exhaust, 128 MJ, dynojet needle on 3rd groove, air-fuel screw 2.5 turns out. In my case the popping came when I went to fully closed throttle from WOT. Bill_P over at Thumper Talk suggested bumping up pilot jet up a size or two. I tried that and the popping is 90% gone. Im now running a #38 PJ. #40 PJ might be better. Bike runs great tho, FWIW.

 

Ding Ding Ding! We have a winner. That's exactly right. Around-town MPG may suffer a bit but the popping will go down.