I have now had the phenomenon twice in the interval of four weeks that the flat belt on the pulley on the 9000 Turbo 2,3 (BJ 94) jumps right up the front when you open the hood. Rolls and straps are ripped and the belt then only runs on three grooves over the roll. I then got on it again, went very hard, so much so you would put a bicycle chain on it again. The strap is so tight, but not as tight as before. I wonder now whether the strap has just been chanted and I just put on a new one or if the pulley tensioner is over there if necessary. How can I find out and how is it blown. The tensioner looks like such a claustrophobic shock absorber.