I was going through and cleaning the carb and noticed that the 2005 and up Honda CRF100's don't have the same pilot screw adjustment (D-wrench style) as the carbs pre-2005 (flat-head style adjustment) Anyone know the reason for this? Seems like it makes it harder to access/screw up. Thanks.
The D style were normally covered with a cap that had to be removed and required a special tool. To keep you from messing with it so you don't make more emissions. Lots of dyno jet, jet kits come with the tool and instructions to remove the caps on sportbikes.
http://miniroadracers.informe.com/forum/tech-questions-f2/xr-crf-100-setup-guide-t2745.html These guys run a spec class and have lots of info for running them stock.