NGK brand spark plug B7HS. This spark plug has a short thread and fits Vespa PK S-XL2 50-125 scooters. The heat range of the B7HS is similar to that of a Bosch W4AC.
When encountering issues with your Vespa's electrical system, replacing the spark plug and the spark plug cap provides a sensible starting point for successful troubleshooting.
Find the right spark plug for your Vespa in the spark plug guide.
