FAQ
TL;DR: On Gilera Typhon/HiPer2, CDI supply on the green wire measures up to 350 V AC; “the voltage should be green with the ignition on.” Test pulser (~130 Ω), grounds, then suspect CDI/coil if spark fades. [Elektroda, DriverMSG, post #16641362]
Why it matters: This FAQ helps Gilera 50 owners fix weak-spark, no-start, or stalls without chasing the wrong parts.
- Typical CDI supply (green wire): 50–350 V AC while cranking; measurement varies by state of charge and RPM. [Elektroda, DriverMSG, post #16641362]
- Pulser/trigger coil resistance: Approx. 130 Ω to ground (red-to-ground). [Elektroda, DriverMSG, post #16641362]
- White wire is ignition ground; any voltage here suggests grounding issues—inspect engine/frame grounds. [Elektroda, BANANvanDYK, post #16641329]
- Weak spark that dies under cranking or after 1 minute often implicates the CDI/ignition coil module. [Elektroda, DriverMSG, post #16642765]
- Runs only on choke? Suspect clogged main/idle jet and verify stock air filter condition. [Elektroda, BANANvanDYK, post #16645879]
Quick Facts
- Typical CDI supply (green wire): 50–350 V AC while cranking; measurement varies by state of charge and RPM. [Elektroda, DriverMSG, post #16641362]
- Pulser/trigger coil resistance: Approx. 130 Ω to ground (red-to-ground). [Elektroda, DriverMSG, post #16641362]
- White wire is ignition ground; any voltage here suggests grounding issues—inspect engine/frame grounds. [Elektroda, BANANvanDYK, post #16641329]
- Weak spark that dies under cranking or after 1 minute often implicates the CDI/ignition coil module. [Elektroda, DriverMSG, post #16642765]
- Runs only on choke? Suspect clogged main/idle jet and verify stock air filter condition. [Elektroda, BANANvanDYK, post #16645879]
How do I fix a weak spark on a Gilera Typhon 50?
Verify the green CDI supply voltage while cranking and confirm the pulser is ~130 Ω. If supply is present and grounds are good, the CDI/ignition coil is the likely fault. Replace the CDI/coil unit after confirming harness integrity and connectors. “Faulty ignition coil - CDI module.” [Elektroda, DriverMSG, post #16642765]
What voltage should be on the green wire from the stator to CDI?
Measure AC on the green wire during cranking. Expect a wide range that should not exceed about 350 V AC. Values depend on cranking speed and battery state. Seeing meaningful AC here confirms the stator’s CDI source coil is working. If green is live and grounds are clean, look to the CDI/coil. [Elektroda, DriverMSG, post #16641362]
Should there be any voltage on the white wire?
No. The white lead is the ignition ground reference. Voltage here points to a ground path problem. Inspect and clean the engine-to-frame ground from the starter mounting bolt to the regulator mounting point. Restore solid grounds before swapping parts. Poor grounds can mimic CDI faults. [Elektroda, BANANvanDYK, post #16641329]
What resistance should I see on the pulser (pickup) coil?
Measure from the red wire to ground with ignition off. The pulser should read about 130 Ω. A reading far from this suggests a pickup issue. A good pulser with weak, fading spark shifts suspicion to CDI/coil or poor grounding. [Elektroda, DriverMSG, post #16641362]
My meter shows 38–43 V on green while cranking. Is that OK?
Yes. Users report around 38–43 V AC on the green lead during starter cranking. That indicates the stator source coil is producing energy. Correlate this with strong grounds and a correct pulser reading to isolate the CDI/coil as the next suspect. [Elektroda, Tom2602, post #16641167]
Engine starts after long cranking, runs ~1 minute, then dies with a wet plug—what’s likely?
A weak CDI/ignition coil can produce an initial spark that degrades as it heats, causing a stall and flooded plug. Replace the CDI/coil after verifying green-wire voltage and pickup resistance. Heat-related failure in the module is a common pattern here. [Elektroda, DriverMSG, post #16642765]
Could the automatic choke (enricher) be the reason it stalls hot?
Yes. A stuck or overactive automatic choke can over-enrich when hot, causing muddy running and stalling. One user found disconnecting the choke allowed a restart after cooling. Test by unplugging the enricher briefly and observing behavior, then service or replace it. [Elektroda, Tom2602, post #16642954]
Carburetor only runs on choke—what should I check first?
Clean the carb thoroughly and ensure the main jet and idle jet are clear. Verify idle air settings and confirm the original, undamaged air filter is installed. If it only runs with extra choke fuel, your main circuit is restricted or airflow is incorrect. [Elektroda, BANANvanDYK, post #16645879]
I replaced the vacuum fuel tap with a manual valve. What about the vacuum port?
Block the carburetor’s vacuum port securely after switching to a manual fuel tap. An open port is a major vacuum leak that will upset fueling and cause stalling or lean conditions. Confirm your block-off is airtight and routed correctly. [Elektroda, BANANvanDYK, post #16649395]
What is the inlet restrictor plate on the manifold and why is it needed?
It’s a perforated plate at the intake spigot that modulates airflow for correct carb signal. Without it, the carb can receive too much air and the engine suffocates or bogs. Ensure this plate is fitted if your setup requires it. [Elektroda, BANANvanDYK, post #16650175]
Can a missing washer under the main jet cause flooding?
No. The main jet seals against the atomizer (sprayer) at the butt joint. It may sit proud of the carb body and still seal correctly. Look elsewhere for flooding, such as float needle wear or incorrect fuel tap choice. [Elektroda, BANANvanDYK, post #16651775]
How do I verify the engine and frame grounds on a Typhon?
Inspect the ground path from the starter mounting bolt on the engine to the regulator mounting bolt on the frame. Clean, tighten, and continuity-check this path. Any corrosion or looseness here can cause weak or disappearing spark symptoms. [Elektroda, BANANvanDYK, post #16641329]
Quick 3-step test: is my CDI/ignition coil bad?
- Measure AC on green while cranking; confirm it’s present and not abnormal.
- Measure pulser resistance red-to-ground; target ~130 Ω.
- If both pass and grounds are solid, substitute the CDI/coil module.
“Voltage should be green with ignition on.” [Elektroda, DriverMSG, post #16641362]
What is a CDI module in this scooter?
The CDI is the capacitor-discharge ignition module that stores and releases energy from the stator’s green lead to fire the coil. In this thread, a fading spark and hot stall were traced to the CDI/coil assembly. Replace it after basic tests. [Elektroda, DriverMSG, post #16642765]
Could a clogged exhaust cause no-start or stalling here?
Yes. A restricted exhaust can choke the engine and mimic fueling faults. Confirm whether your exhaust is stock or tuned, and inspect for blockages or carbon buildup if symptoms persist after carb service. [Elektroda, BANANvanDYK, post #16649395]
What mixture screw setting should I expect after cleaning?
Start from a typical baseline then fine-tune, but if it only idles with the screw barely out and the plug floods, look for air leaks or fuel delivery issues first. Non-vacuum taps can overfeed if the float needle leaks. [Elektroda, Tom2602, post #16648117]
