Slack or incorrectly adjusted chains cause hard or snatchy running and excessive wear. The adjustment of both chains should be such that there is about ½-in. free up and down movement midway between the sprockets. Check the adjustment of the front chain through the inspection hole in the chain cover - never attempt to check with chains in motion - an elementary point which if forgotten may result in the loss of, or injury to, the fingers. Always check the adjustment in several places and allow the specified amount of freedom in the tightest place. The tension is nearly always found to vary slightly in different places as the sprockets are turned.