Background: Read the two pages and a good thread with ~ response(s). My bike is 90% MX and 10% Hare/Trail ridden, all stock jetting, at 700ft ASL with 80deg F temps currently, I run 100oct unleaded pump gas in it 99% of the time. Recently went to a TwinAir filter(left the screen/frame in) which I could tell immediately that the bike is getting more air, leaned it out somewhat. Had to adjust the Pilot circuit out to 2 turns to get it to idle again. Noticed on trail/field riding that the bike has decel backfiring in 4th and 5th gears after WOT on long straits, seems pretty crisp everywhere else(small bog still there but I haven't played with the accel pump/circuit as its not critical for me).
Question: At what point do I need to change to a different pilot jet? Going to try another 1/2 turn next ride and see what happens. The backfiring is not noticible on a track, only under high-speed runs/decel(I need to remove a tooth or two on the rear sprocket too... bike top end is a little short). Also are there any other changes to the main jet, needle, that would be recommended from the stock settings? Seems the pilot circuit is likely the one to focus on for this but I want to make sure I'm not missing something. Familiar with auto carbs and tweaks, this one is not too different. Bike starts on 1st or second kick when cold, 1st or 2nd with hot-start/lean-air lever when hot...
Thanks,