Adjusting valves

If the scooter makes a clicking sound, or when the scooter hisses, pops or flops you may need to service the valves. Also difficulties starting the scooter, or power losses can be a consequence of problems with the valves. The clearance between valve and rocker arm can be an issue, or the valves can be burned.

How valves operate and why adjusting

When gasses should go in or out, the valves are pressed open by the rocker arms.
When compression needs to be build, it is of great importance that the combustion chamber is completely air-tight. If there’s no clearance between the valve and the rocker arm in the compression mode, the rocker arm still is in contact with the valve. This automatically means that the valve does not close for 100%. Therefore, the design is such that there’s always a small gap between valve and rocker arm, so the valves still closes correctly at operating temperature.
Therefore, the design is such that there’s always a small gap between valve and rocker arm, so the valves still closes correctly at operating temperature.