got a free spirts tensoner tonight to play with ,not realy sure why marks died , 1 these babys need pullig apart to re lube the pivot pin & plain bearing from time to time ,the one im playing with the lube was drying out so movement was stiff , 2 ,on assembly the side plates pivot pin retaing countersunk socket caps will have been threadlocked on assembly & ONLY screwed in enough to give zero clearence between the side plates & mounting arm OR ELSE the side plates will bind aganst the mounting arm ,3 the thread end of the rod eye should hit the mounting arm & act as a posative stop for travel of ideler wheel on overrun as the lower belt run becomes the tight side for a splt second compressing the spring ,thus preventing the roll pin from loading up in its grooves in the side plates ,the grooves do give 20 mm of travel in the ideler wheel when off the bike & plenty of movement on the bike ,