set the cams to TDC(make sure the timing belt between the two cams is tight or these instructions will not work) then set the crank about 2 degres before TDC(with a little slack in the belt between the ex. cam and the crank) . loosen the tensiner then pull the tensiner tight and spin the crank(counter clock wise) to take the slack out of the belt. this shoyld take all the slack out of the belt. hope you understand that, thats how i had to do mine cuz my T belt was doing the same as yours.
steve