Piaggio 438074 Original Champion Spark Plug RG6YCA – NRG PureJet, Gilera Runner and Aprilia SR 50

The original Piaggio 438074 spark plug, which in the catalog is the Champion RG6YCA: this is the spark plug for 50cc two-stroke PureJet and Ditech direct injection engines – Piaggio NRG PureJet, Gilera Runner 50 PureJet and Aprilia SR 50 injection. It's not just any spark plug: on these engines, the mixture is injected directly into the combustion chamber and the spark plug must ignite a stratified charge, with a specially chosen heat range and electrode geometry. Installing an "equivalent" one by eye is the quickest way to end up with an unstable idle, engine jerking during acceleration, and the injection warning light on.

✓ Strengths

• It is the original equipment spark plug, the one specified by Piaggio for the PureJet: the correct heat range and electrode gap are already set.
• Resistive (the "R" in RG6YCA): shielded against electromagnetic interference, essential for an engine managed by an ECU.
• Projected electrode: the spark works deeper into the chamber, as required for a stratified charge.
• One code for three brands: NRG, Runner, and injection SR all use this.
• It costs just a few euros and is the first thing to change when a PureJet starts poorly or doesn't hold idle.
• Ø 10 mm thread with flat seat and gasket: tightens with a 16 mm spark plug wrench.

Technical features

Vehicle compatibility

List taken from the official Piaggio spare parts catalog (B2B area), families "APRILIA - SR", "GILERA - Runner 50", "PIAGGIO - NRG" and their respective Historic Catalogs 1998-2005. If your vehicle is not in the table, send us the VIN and we will check it for you.

Perfect for

• Those with a PureJet or Ditech that starts with difficulty, doesn't hold idle, or jerks on acceleration: the spark plug is the first thing to rule out.
• Workshops that still service these direct injection engines and want the correct spark plug, not just an equivalent from a chart.
• Those who do their own maintenance and want to keep a spare: it's inexpensive and doesn't expire.
• Those who bought a scooter that has been sitting for years and are restarting a PureJet.

Frequently Asked Questions

Is it suitable for my scooter?
It is suitable for Aprilia SR 50 injection (2003-2014), Gilera Runner 50 PureJet, and Piaggio NRG / NRG Power PureJet. The table above comes from the official Piaggio spare parts catalog.

What is the difference between RG6YCA and RG6YC?
They are two different spark plugs: the RG6YC is Piaggio code 438073. If your catalog indicates RG6YC, this is not the one you need.

Can I install an equivalent NGK or Denso?
Conversion charts indicate NGK CPR8E or CPR6EB-9, Denso U24ESR-N, Brisk AR12YS. These are indicative equivalents: for a direct injection engine, it is advisable to stick to the original equipment spark plug.

What electrode gap should I set?
The spark plug arrives with the factory gap, around 0.6 mm. Check it with a feeler gauge and do not adjust it by eye.

How often should it be changed?
Follow the maintenance schedule in your manual. On these engines, it is still advisable to remove it and inspect it at every service: the color of the insulator says a lot about how the injection is working.

I changed the spark plug but nothing changed: now what?
On a PureJet, symptoms of difficult starting and irregular idle often come from the injector, fuel pump, or sensors. The spark plug should be ruled out first precisely because it's inexpensive, but if it doesn't solve the problem, diagnosis is needed.