My bike has been loading up a lot on very slow rides with my son (modified KDX 250). I've changed the filter, the muffler packing, run a BR7 plug. But here's what I'm wondering.
The local used motorcycle dealer told me that on older two strokes often the slide wears in the carb from all the vibration over the years and changing it will eliminate the fouling problem.
I belive there are some KDX250 riders who went to a different slide cutaway with good results; do a search on the topic, research jetting, reply with your current setup, sit tight, or all the above...
Bruce,
While the slide will wear some over time as will the aluminum carb body that it rides in. This doesn't seem to be the case with your bike. If you have ruled out other possible causes such as worn reeds, it could be that you have some wear on your needle and or needle jet. This is also common over time and the fix is usually to move to the next size leaner needle. As it is getting warmer out though, it could be as simple as an air screw adjustment.--Dan