KYMCO XCITING S 400 Manual page 120

3. Engine > Valves XCITING 400i
Coat the valve stem in fresh engine oil and insert the valve into the valve
guide and through the seal. Turn the valve slowly as it is inserted. If you
are installing a new valve you must ream the valve guide first. Make sure
the valve will move smoothly in the valve guide without wobble.
Install the valve springs. The tightly coiled end of the springs should sit
against the spring seat.
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