Product Details
Ignition Coil - Vespa GTS 250/300
Compatibility / Fitment
Use the fitment details below to confirm this part matches your scooter before ordering.
- Engine Code: 139QMB
- Fits Models / Common Applications: Vespa and other compatible models may apply.
Fitment Guide: This compatibility information is based on manufacturer and supplier data. Listed models are common known applications and may not include every compatible scooter. If your scooter has multiple versions or production changes, confirm the correct match before ordering. Check photos, measurements, original part numbers, engine code, model, and related fitment information whenever possible.
Common Fitment Questions
Q: Will this fit a 139QMB engine?
A: This SKU is listed as compatible with 139QMB engine-code fitment. Always compare your original part and scooter details before ordering.
Q: Will this fit a Vespa?
A: This SKU is listed with Vespa model fitment where the scooter also matches the listed engine or fitment notes.
Additional information
RMS Ignition Coil – Vespa GTS 250/300
A weak or failing ignition coil is one of the most misdiagnosed problems on fuel-injected Vespas. If your GTS is misfiring at idle, stumbling under load, or refusing to start despite a good battery and fresh spark plug, the coil is the first place to look. This high-quality RMS aftermarket replacement restores full high-voltage spark output to your ignition system, ensuring clean, complete combustion across the entire RPM range.
Key Features
Full Spark Output: Engineered to deliver the correct high-voltage pulse to the spark plug cap, restoring crisp throttle response and eliminating misfires.
OEM-Spec Winding: Internal primary and secondary coil windings matched to Piaggio's original resistance specifications for a true drop-in replacement.
Heat-Resistant Epoxy Potting: Coil internals are sealed in high-temperature epoxy to protect against vibration, moisture ingress, and thermal cycling.
Direct Connector Match: Factory-matched electrical connector plugs directly into the GTS ignition harness — no splicing, adapters, or modifications required.
Fitment Guide
Technical Specs
Part Number: 58120R-AFT
Replaces OEM: Piaggio / Vespa ignition coil for Quasar 250–300cc engines
Voltage: 12V DC input
Output: High-voltage secondary winding (standard CDI/TCI compatible)
Connector: Factory-matched multi-pin plug
Manufacturer: RMS (Italy)
Maintenance Note: Before condemning the coil, always check the spark plug cap resistance (should be ~5kO) and the plug itself. A carbon-tracked or fouled plug can mimic a dead coil by bleeding off the high-voltage pulse before it fires.
Installation Tip: The ignition coil on the GTS is tucked behind the left side body panel near the airbox. Remove the panel carefully and disconnect the coil's two-pin connector and the plug cap before unbolting the coil bracket — it's a 10-minute job with the right trim tools.
Pro Tip: When reinstalling, apply a small amount of dielectric grease inside the spark plug cap before pressing it onto the plug. This prevents moisture from wicking into the cap and causing intermittent misfires on damp mornings.
WARNING: California Proposition 65




