I have just taken my PX200 carb apart, cleaned it and put it back together with new seals etc. No reason, just to see what was in there. (Is this just a scooterist and biker thing?) Anyway, I have not changed jetting, but of course the pilot mixture screw is now way out of adjustment. That’s the one you can’t get at, you have to send a trained spider in to adjust it.
Dredging up past memories of fooling around with carbs and jetting, am I right in thinking this screw affects mostly (but not only) idling and dogging along in traffic? And turning it outwards (anti-clockwise) will make the mixture leaner? At the moment the nose of the plug is sooty, which I believe shows the primary circuit is too rich. The main jet shows on the porcelain, deeper inside the plug?
The bike runs great the faster we go, round town and in traffic gets very four-stroky, if you know what I mean!