It's interesting how times have changed. Back in prehistoric times the first thing to inspect with a problem like pipsters' was the spark plugs because they often fouled out due to the leaded gas, flooding, excess oil consumption, weak spark, wrong gap, etc. Nowadays, what with unleaded gas, EFI, ECU and closer engine tolerances, spark plugs are good for so many miles we now overlook them as the culprit, or as a diagnostic tool, especially when it is not easy to access them, as is the case in our scooters.