Thanks for all info. I hadn't the stopper, but I made one myself from aluminium. The timing belt itself is installed correctly and also tthe tension is correct, the auto-tensioner works fine. The problem was the tension of the balancer belt - it seems to be poor in comparsion to the "strong" tension of the timing belt. Someone here said that it is normal that the balancer belt has smaller tension than the timing belt. If so, everything is fine. Of course I made several turns and then tightened the adjusting bolt. It is H22A2, 1995.