Jetting Question

OK,
I've been trying to track the reason for my backfiring of my XR. The valves are in spec. boots, headers, etc are tight. The bike is uncorked with the proper needle and seat, 175 main (I live at ~300 ft), 68S pilot, and Unifilter. What I am finding is as I adjust my pilot screw CW, it makes no difference in idle and as I turn it CCW, the idle begins to drop. This is telling me that my pilot jet is too large. Does this seem right? Is there anyone else running a 65 pilot jet with an uncorked bike at close to sea level? Thanks in advance for any help.

-Mike

Check this out.

http://borynack.com/XR650R/xr650r_caruretor.htm

You might find the exhaust has a leak at some point, probably where the muffler joins the headers, and is sucking a little air on the over-run, mixing with unburnt juice in the exhaust, and going pop. Thats what mine was doing anyway until I hit the joint with some hi-temp silicone.
Still does it now and again though.
...meh...
At least the blue / orange flame looks funky..