i think i may have solved the belt issue, at least in my case. over the past few days i have been testing the slipper plates and the last few times i didnt bother putting the lower screws back on the gear cover. well i noticed that when you "bow" the chassis the rear part of the belt guide moves quite a bit to the right , enough that it twist the belt on the upper side. and i retightend the chassis screws that hold the rear section to the middle. between all of that the top cover berely moves anymore and should solve the problem, will see tomorrow.