I was having a running problem with my yz so i took off the carb and replaced the accel pump diaphram and spring, cleaned jets and checked everything else, was ok till i took off top side of carb and found the whole slide area full of somekind of mud! ***! seen a little before but this was unaccptable! i say mud but it was a mixture of fuel reisidue and carbon and maybe teflon from slide, as it was worn? dunno anyone ever seen this before?