The factory manual for the models from 1992 on describe an adjusting method which in my opinion makes sense for the older models, too. Thus the balancer chain tightens up between the lower balancer shaft, the upper balancer shaft, and the crank shaft, and all the chain slack is taken up automatically by the chain adjuster spring. Now fix the four adjuster screws starting with the right one of the big allen bolts. If you put some grease on the side cover gasket before reassembling, you might take it off easily next time and reuse it one more time. After five tries I finally succeeded with this.
Motor has to be cold .
One of them, the small grove, is ours. To be sure check the position of the piston with a long screw driver through the spark plug hole. You can feel the clearence of the rocker lever with your fingers. Before you measure the clearence rock the rocker a little and then lift it up. If much more turning is needed on outlet valves they may be burnt and have to be replaced.