carb or electrical problem?

[joeeyyy]

pevious problem with my banshee was at this stage:

just recently had a trip to buttercup dunes(imperial sand dunes) and my banshee had two good runs up the hill and ran fine in the bowls then all of a suddenly the bike began to bog in second alot while in the bowls and it wouldn't run the hill either it would shift into first and second and would bog out in third half way up the hill, this bike usually could pull 3rd and 4th up the hill before but all of a sudden the powerband was gone in third and it bogged in second in the bowels, where do i start i just had it dynoed it was 55hp. had it jetted for the dunes the only thing i changed was my gas and oil mixture i went from 50:1 vp c12 with power plus to trick 40:1 with benol would this have effect my powerband and cause it to bogg?

now my problem is:

cleaned out the carbs and went back to my old mixture with gas and oil(vp and powerpplus) but their is still no power and one pipe smokes quite a bit more than the other and that cylinder and pipe do not get hot when the bike is running, i tried opening it up down the street and as soon i slowed it would die and have trouble kicking back on, after riding it for about 7 min. i pulled the plugs and one was turning a light brown and the other was brand new looking as it was when i took it out of the box(it came from the side that was smoking alot and not heating up) the only things that i have touched was the gas and oil types and mixtures but i returned those to original, i also fooled with the the air/fuel mixture screw a bit but would that cause this much of a problem? what does it sound like to you? where do i start? also i checked the reeds they were fine