Chris-NJ,
I think you're on the right track. It is sometimes good practice to change one thing at a time to help determine which changes make the biggest differences. It may be a combination of a couple of things including jetting.
If you suspect that transporting your bike may have something to do with the problem, you may want to try draining the carburetor of it's gas before putting it in your truck. I suggest the following:
Start the bike up let it worm up at home (ride it around a little if you can) before killing the motor, turn off the gas and let it run for a couple of minutes, then shut off the engine (try not to let it run out of gas, it can get too lean if your jetting is off).
Pull gas line an ensure your gas is shutting off.
Next find a good place to lay your bike on its side and lay it completely over and drain off the excess gas from the bowl through the vent tubes.
If the gas shuts off properly, replace your fuel line and transport your machine.
When you go to start the bike at your destination, turn on the gas, wait about 30 seconds and then lean your bike over far enough that gas comes out the vent tubes, choke, give it a couple of slow kicks and then the bike should fire on the first good kick. I generally turn it off the choke in less than 30 seconds after start up.
If your are successful, try it again on the way home and see if you can make it run without fouling the plug each time it is transported.
I also agree that you should consider replacing the stock bazooka silencer with a nice OEM version. Less spooge greater performance!
Here are my jetting specs
2000 300 EXC
600 to 1000 ft.
# 6 slide
R1466N needle 3rd clip
175 main
42 pilot and 40 pilot (summer) AM 2.0 to 2.5 turns.
44:1 Mobil XT2, mixing 2.5 gallons of CAM gas to 2.5 gallons of 93 octane, the higher octane helps prevent power valve knock on deceleration.
stock pipe
FMF power core II
There are lots of posts on the subject of the #7 slide and the single taper Honda needles. You should search this forum and others on the subject. I purchased my bike four months old and the guy that I got it from had already worked out the jetting (with help from G.C.) and I love the way it performs.
Please let us know if you resolve your plug fouling problems.
tomthumb