NGK Spark Plug LKAR8A-9 (4786) – OEM-Grade Plug for KTM Duke/RC/Adventure 125/200/250/390, Bajaj Pulsar NS200/RS200/AS200 (Center), Dominar 250/400 (Center), Husqvarna 401

If your KTM, Husqvarna or Pulsar/Dominar triple-spark feels hard to start, rough at idle or flat on top-end, chances are the stock plug is tired. NGK LKAR8A-9 (Stock #4786) is the factory-equivalent nickel spark plug specified for many KTM 125–390 singles and used as the center plug on several Bajaj Triple-Spark engines. It keeps the exact OE dimensions—M12 × 1.25 thread, 26.5 mm reach, 14 mm hex, gasket seat, 0.9 mm gap, heat range 8—so it drops in without any spacers or guesswork. 

The projected-tip nickel center and ground electrodes provide a strong, stable spark, giving cleaner combustion and easier cold starts in real Indian traffic and weather. NGK’s 5 kΩ resistor design protects ECUs, injectors and sensors from interference, making LKAR8A-9 safe for BS4/BS6 EFI bikes with oxygen sensors. 

On Pulsar NS/RS/AS200 and Dominar 250/400, LKAR8A-9 is widely used as the center plug in combination with two side plugs (CPR8EA-9/CPR8EAIX-9), restoring crisp throttle and smoother cruising when the original center plug is worn. NGK’s own part finder lists LKAR8A-9 as the correct central plug for Pulsar 200 NS triple-spark. 

Why buy from Under The Hood?
You get 100% genuine NGK stock, GST invoice, careful packing and guidance from a workshop that actually tunes and services these exact bikes—so you’re not guessing when it comes to plugs or heat ranges.

Key Features

• Genuine NGK Standard Plug – Original LKAR8A-9 / 4786 nickel spark plug; OE-equivalent for KTM 125–390 and many Bajaj triple-spark engines. 

• Correct OE Specs – Thread 12 mm × 1.25, reach 26.5 mm, 14 mm hex, gasket seat, 0.9 mm preset gap, heat range 8, 5 kΩ resistor – matches KTM/Bajaj/Husqvarna requirements. 

• Projected-Tip Nickel Electrodes – Proven design for reliable spark, clean burn and solid service life in hot, dusty Indian riding. 

• Direct Fit for KTM 125–390 Singles & Husqvarna 401 – Listed as replacement for OE KTM/Husqvarna part numbers like 90239093000 / 90139093100 on multiple catalogues.

• Center Plug for Bajaj Triple-Spark – NGK part finder confirms LKAR8A-9 as the center spark plug on Pulsar 200 NS (2 × CPR8EA-9 + 1 × LKAR8A-9). Also widely used for RS/AS200 & Dominar 250/400 center positions. 

• EFI & BS6-Friendly – Resistor construction keeps electrical noise low for bikes with ECUs, fuel injection and O2 sensors, supporting stable fueling and diagnostics. 

• Balanced Performance & Economy – Correct heat range and projected tip help maintain easy starts, smooth idle and consistent mileage when your old plug is fouled or eroded. 

• Global Availability – Common plug code used worldwide across KTM/Husqvarna models, making future replacements easy. 

• Upgrade Path Ready – Riders wanting even longer life can move to NGK LKAR8AI-9 Laser Iridium, which shares the same fit/heat range (also listed on Under The Hood). U

• Under The Hood Backing – Genuine stock only; no loose/duplicate plugs, plus phone/WhatsApp support if you’re unsure about your bike’s plug code.

Compatibility Table

CONFIRM PART NUMBER BEFORE PURCHASE

Variants

• Standard:

  • NGK LKAR8A-9 (4786) – Nickel, OEM-Grade

  • Ideal for riders who want stock-spec reliability with easy availability and low running cost.

• Upgrade (sold separately, ):

  • NGK LKAR8AI-9 (6706) – Laser Iridium – Same dimensions and heat range but with iridium center + platinum ground for longer life and stronger spark. Best for heavy touring or performance-focused riders. 

What’s in the Box

• 1 × NGK LKAR8A-9 (4786) Standard Nickel Spark Plug in original NGK box

8️⃣ Installation & Maintenance Notes

• Always work on a stone-cold engine to avoid damaging the aluminium head threads. 

• LKAR8A-9 comes pre-gapped at 0.9 mm. Normally you don’t need to change this; if your manual specifies a different gap, adjust gently and never lever directly on the center electrode.

• Use a 14 mm spark plug socket and torque to manufacturer spec (typical range for M12 plugs in alu heads is around 14–20 Nm). 

• On triple-spark Bajaj engines, replace only the center plug with LKAR8A-9; the two side plugs use CPR8EA-9 / CPR8EAIX-9 and must match OE spec. 

• Check plugs at each major service for erosion, carbon, oily deposits or cracked insulators. Replace sooner if you ride mostly in stop-go traffic, dusty conditions or at very high rpm.

 FAQs 

Q1. Will NGK LKAR8A-9 fit my KTM Duke/RC 200 or 390?
Yes. LKAR8A-9 is an OE-equivalent NGK plug for KTM 125/200/250/390 Duke and RC models, replacing KTM plug part numbers like 78039093000 / 90239093000. It has the same thread, reach, hex and heat range as the stock plug. 

Q2. Is this the correct center plug for Pulsar NS200?
Yes. NGK’s official part finder lists LKAR8A-9 (4786) as the center plug on Pulsar 200 NS, with two CPR8EA-9 plugs on the sides. If your existing center plug carries the same code, this is the correct replacement. 

Q3. Can I use LKAR8A-9 on Dominar 250/400?
Many catalogues and sellers list LKAR8A-9 as the center plug on Dominar 250/400 triple-spark engines, and riders commonly run it without issues. However, Bajaj also uses Iridium center plugs on some variants, so always confirm against your owner’s manual or the plug you remove before ordering. 

Q4. What’s the difference between LKAR8A-9 and LKAR8AI-9?
LKAR8A-9 is a standard nickel plug with projected tip. LKAR8AI-9 is the Laser Iridium upgrade: same size and heat range, but with a 0.6 mm iridium center and platinum ground pad for longer life and stronger spark. Performance-oriented or high-mileage riders generally prefer LKAR8AI-9. 

Q5. Will this plug change my mileage or engine warranty?
Because LKAR8A-9 matches the OE heat range and dimensions, it behaves like a stock plug on listed models and should not negatively affect mileage or warranty when installed correctly. Using the wrong heat range or over-tightening, however, can cause engine or thread damage—so always install carefully or ask a professional.

NGK LKAR8AI-9 (iridium)