1一台金牛牌ZH1105型三轮农用运输车在行驶途中，其空气滤清器发出“咚咚”的声音。机手停车后检查，发现是排气门间隙过大造成的。由于排气门间隙过大，则气缸在排气行程不能将废气排尽，当进气门开启后，气缸内剩余的废气便会猛冲入进气道产生“咚咚”的响声。为此，修理工按 1 Taurus ZH1105 three-wheeled agricultural vehicles on the road, the air filter issued a “pound” sound. After the parking lot inspection, it is found that the exhaust valve clearance caused by too much. As the exhaust valve clearance is too large, the cylinder exhaust exhaust stroke can not be exhausted, when the intake valve is open, the remaining gas in the cylinder will fierce into the inlet to produce a “pounding” sound. To do this, the mechanic presses