NGK Iridium IX Spark Plug Kit for Royal Enfield UCE Twin-Spark 350 (BS3/BS4) – BPR5EIX + CPR6EAIX-9S

The NGK Iridium IX twin-spark kit — BPR5EIX + CPR6EAIX-9S — is the complete iridium ignition set for Royal Enfield's UCE twin-spark 350 engine. These motors run two plugs per cylinder (a main and an auxiliary), and this kit gives you both in one box, matched to NGK's recommended iridium spec.

Both plugs use a 0.6mm fine-wire iridium centre electrode for a sharper, more focused spark than standard copper plugs. On the twin-spark UCE motor that translates to cleaner combustion, smoother idle, and more reliable cold starts — and because iridium holds its gap far longer, you get consistent ignition service after service.

This is a direct-fit OEM-spec set. It doesn't alter your tune or compression — it restores and maintains the ignition the way the engine was built to run.

Fitment (NGK-confirmed — UCE Twin-Spark 350)

• Royal Enfield Thunderbird 350 / 350X (ABS Dual Channel)
• Royal Enfield Classic 350 (UCE / BS3 & BS4)
• Royal Enfield Bullet (Trials)
• Royal Enfield Electra 350 BS3 (2015)

This kit is for the UCE twin-spark 350 (BS3/BS4) which uses two plugs. Riding a newer BS6 J-series Classic 350 or Bullet 350? That engine uses a single BPR5EIX — order our single-plug listing instead. Not sure which engine you have? Message us on WhatsApp.

Specifications

• Brand: NGK
• Part Numbers: BPR5EIX + CPR6EAIX-9S
• Type: Iridium IX Spark Plug Kit (2 plugs)
• Centre Electrode: Iridium, 0.6mm fine-wire
• Application: Royal Enfield UCE twin-spark 350 (BS3/BS4) ignition
• Sold as: 2-plug set (one BPR5EIX + one CPR6EAIX-9S)

Key Features

• Complete twin-spark iridium set — both plugs the UCE 350 needs
• NGK-recommended iridium fitment for the UCE twin-spark 350
• Fine-wire iridium electrodes for a sharper, more focused spark
• Smoother idle and better cold starts versus standard plugs
• Long service life — iridium holds its gap between changes