The 19 phbg (96 jet, w10 needle 3rd position) on my peugeot 103 (70 kit, simo pipe, 4 petal adaptor) seems to have a spot at about half throttle where it just kills the bike. It sounds just like if you hit the kill switch on the bike with no combustion noise at all, not lean not ritch nothing, but if you give it more gas the bike is fine again.
It happens mainly below about 4000-5000 rpm's and if I don't move the throttle will kill the bike completely. I am assuming that there is just a strange super rich or lean condition happening and was wondering if anyone ever ran into any similar problems.
I have messed with the jetting and needle position/size but the bike doesn't run nearly as well as with the setup I'm using.