CDI PIAGGIO for Vespa ET4/LX/S
50ccm 4T AC, 2-Ventil
also for APRILIA/PIAGGIO Sca..
The ignition coils factory fitted to the 50cc two-stroke motors and also the 50cc two-valved four-stroke motors already have an integrated CDI unit (Electronic Regulator). All other models, with a carburettor fitted, possess separate ignition coil and CDI components. Ignition coils are exposed to intensive use and can fail because of this. If your motor starts to misfire, it is mostly due to the ignition coils failing. The only effective answer is immediate replacement.
SIP-TIP : To help protect against harmful corrosion all electrical connections should be treated with WD-40 (#14253000) or similar.
OEM Numbers (for the purpose of comparison)
639978 - 638877 (PIAGGIO)