Been playing around to with my fuel ratio at idle. Currently set at 4% CO which translates to about 13:1 air to fuel. This would be still slightly on the rich side for what's considered normal for a air cooled engine, in the automotive world anyway. strangely when I set idle mixture using the dead cylinder method and then check the co it comes in about 5-6% co, or about 12:1. I've been curious to see how much further I can lean it out but I have decided this is going to be too lean, I started getting some lean back firing on decel today after setting it at 4% co. Seems around 5% is about perfect, for this bike anyway. Secondly using The gas sniffer ensures a perfect idle fuel mixture for both cylinders, every time I have checked the co after doing a dead cylinder method adjustment the mixtures are still a bit out from each other