Well here it is again. The only mod I did to my stock 04 DS650 is I opened up the end cap on the exhaust. The problem I'm having is when at a stop I go to give it gas and I get a popping under my seat once in a while. I know the bike is backfiring and I was told to open up the air screw another 1/4 turn. I was told the bike is running to lean and that is why its popping. Could someone please look in their service manual and tell me what the air/Idle screw is supposed to be set at stock.I now have it set out exactly 3 1/2 turns. I was told to open up the air/idle screw to make it run richer but doesn't opening it up more lean it out ? Any help here would be much appreciated. Thanks, D

 

Its a mixture screw, so going out is richer. If you get to 4 turns out, and its still got lean symptoms, you need a bigger pilot jet.