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Ignitions and Electrical› Ignition Components

Denso

Iridium Power Spark Plug

$23.99 $16.96 Save $7.03

SKU: IU31

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Overview

The Denso IU31 is an Iridium Power spark plug designed to improve firing performance. It features a 0.4mm iridium tipped fine wire center electrode and a U-Groove ground electrode with a taper cut shape. The spark plug has machine-rolled threads to prevent seizing and a purified alumina powder insulator for strength and thermal conductivity.
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The Denso IU31 Iridium Power spark plug is engineered for enhanced firing performance through its advanced design. It utilizes a 0.4mm iridium-tipped, laser-welded fine wire center electrode, which requires less voltage for a stronger spark. The U-Groove ground electrode, featuring a taper cut shape, further boosts ignitability while minimizing quenching. Constructed with precision, this spark plug includes machine-rolled threads to ensure smooth installation and removal without cross-threading or seizing. The insulator is made from purified alumina powder, providing exceptional strength and superior thermal conductivity, while its five-rib design effectively prevents flashover. A copper-glass seal ensures a gas-tight connection between the center electrode and the insulator. Key specifications include a 10mm thread diameter with a 1.0mm pitch, a gasket seat type, and a 19mm reach. The hex size is 5/8" (16mm), and it features a removable nut terminal type. The pre-set gap is .035" (0.9mm). This plug is also a resistor type, with a value of 5k Ohm, and has a heat range of 31. Torque specifications are provided for both cast iron and aluminum engines, recommended at 7-11 lb. ft. While classified as an automotive part, the available fitment data indicates applications primarily in powersports, specifically for the Suzuki DR650SE Base model from 1996 to 2007. No automotive applications are currently associated with this part.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandDenso
Part NumberIU31
CategoryIgnitions and Electrical
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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