1995-2000 ATK 250 LQ Spark Plug Replacement and Upgrade Guide
Keep your ATK's two-stroke engine firing perfectly with the right spark plug.
- The standard NGK B8ES or Denso W24ES-U are excellent, affordable choices for the ATK 250 LQ.
- Changing a spark plug is a very easy and fast maintenance task you can do yourself.
- Repeatedly fouled plugs indicate your bike is running too rich; investigate your carburetor jetting or air filter.
- Consider carrying a spare, inexpensive standard copper plug in your trail kit for quick fixes.
Is Your ATK 250 LQ's Spark Plug Failing?
A bad spark plug can cause a range of problems that are often mistaken for more serious engine or carburetor issues. Because it's an inexpensive and easy part to replace, checking your spark plug is a great first step in troubleshooting. Pay attention to these signs:
- Hard Starting: If your bike is suddenly difficult to start, either cold or after it's warmed up, a weak or fouled plug 🎬 Watch these 12 tips for fixing a hard starting engine. could be the culprit.
- Misfiring or Stuttering: A bike that hesitates, sputters, or runs rough, especially under acceleration, may not be getting a consistent spark.
- Fouling: This is a common issue on two-strokes. A fouled plug will be black, wet, or oily. This happens when the engine runs too rich (too much fuel or oil) or doesn't get hot enough to burn off deposits.
- Poor Performance: A noticeable loss of power, poor throttle response, and bad fuel economy can all point to a spark plug that is past its prime.
Two-Stroke Specific: Reading the Plug
On a two-stroke like the 250 LQ, the condition of your spark plug tells a story about your engine's health. 🎬 Learn the four main reasons why dirt bikes eat spark plugs. A plug that is constantly wet with fuel or black with oily residue (fouling) often points to carburetor jetting that is too rich for your riding conditions or an incorrect fuel/oil mixture. While a new plug will get you running again, repeated fouling means you should investigate your carb settings to prevent future issues.
Choosing the Right Aftermarket Spark Plug
For the 1995-2000 ATK 250 LQ, you don't need to spend a fortune on a spark plug. The original Rotax engine was designed for simple, reliable components. All three major brands—NGK, Denso, and Champion—offer excellent, affordable options that meet or exceed OEM quality.
Brand Tiers for Your ATK
- Standard & Reliable (Good): A standard copper plug from NGK, Denso, or Champion is the workhorse choice. They provide excellent performance and are very affordable. The NGK B8ES and Denso W24ES-U are common, reliable choices for this bike. The Champion equivalent is the N2C. These are perfect for most riders.
- Long-Life & Performance (Better): If you want a longer service interval and a slightly more robust spark, an Iridium plug like the NGK BR8EIX is a great upgrade. Iridium plugs have a finer electrode, which can improve starting and resist fouling a bit better than standard plugs. They cost more upfront but can last significantly longer.
Pro Tip: The ATK 250 LQ is a two-stroke off-road bike. You'll likely be changing plugs more often due to the potential for fouling than from wear. Many experienced riders keep a few extra standard copper plugs in their toolkit. They are inexpensive and easy to swap on the trail if one gets fouled.
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (Standard Copper) | $3.74 - $8.00 |
| New Aftermarket (Iridium) | $10.00 - $25.00 |
| High-Performance/Multi-Electrode | $17.00 - $55.77 |
Frequently Asked Questions (FAQ)
What is the correct spark plug for my 1995-2000 ATK 250 LQ?
The most commonly referenced standard spark plugs are the NGK B8ES and the cross-referenced Denso W24ES-U and Champion N2C. An iridium upgrade option is the NGK BR8EIX. Always check the manufacturer's latest fitment guide to be certain.
Do I need to gap my new spark plug?
Yes, you should always check the gap before installation, even if the plug is pre-gapped. The recommended gap is typically around 0.8mm (0.031"). A feeler gauge is a simple tool used to verify this measurement.
Why does my bike keep fouling spark plugs?
For a two-stroke like the 250 LQ, frequent plug fouling is almost always caused by a rich running condition. This means there's too much fuel and/or oil in the combustion chamber. Common causes include incorrect carburetor jetting, a dirty air filter restricting airflow, or an improper oil-to-gas ratio.
🎬 Follow this guide to stop your two-stroke from fouling plugs.How often should I change the spark plug on my ATK 250 LQ?
There isn't a strict mileage interval like on a street bike. For an off-road two-stroke, it's best to inspect the plug regularly and replace it when the electrode becomes worn or if you experience fouling or hard starting. Many riders replace them once a season or carry a spare to change as needed.
Is an expensive iridium spark plug worth it for my bike?
It can be. Iridium plugs offer a longer lifespan and can provide a more consistent spark, which may help with starting and reduce fouling slightly. However, given the low cost of standard plugs and the nature of two-stroke engines, many riders prefer to stick with standard copper plugs and change them more frequently.
Helpful Videos
![2 Stroke Dirt Bike Keeps Fouling Plugs? [How To Fix It]](https://img.youtube.com/vi/xgW5oW5GKF4/mqdefault.jpg)
![The 4 Ways Dirt Bikes EAT Spark Plugs [Why Did It Foul?]](https://img.youtube.com/vi/0HsdViNKD8Q/mqdefault.jpg)
Technical Specifications
Thread Size: 14mm, Hex Size: 13/16" (21mm), Reach: 19mm (3/4"), Gap: 0.8mm (0.031"). Common plugs are NGK B8ES, Denso W24ES-U, and Champion N2C.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- ATK 250 LQ: