The following wearing parts must be purchased: 4 or 6 matching spark plugs.
1. Remove the spark plugs.
2. Measure the gap between the electrodes (2) with a feeler gauge. Specified value: 0.8 mm. New spark plugs usually have the gap between the electrodes adjusted correctly.
3. To adjust the gap between the contacts, bend the side electrode (1). There is a simple, practical tool (3) for this; if you don't have one, tap it from the side with a hammer in the direction of the side electrode.
4. When bending, support the spark plug thread flange with a small screwdriver, but never on the central electrode (4), otherwise this electrode will be damaged.
5. Install the spark plugs.