Choosing the Right Spark Plugs for Your 1981 Suzuki GS550T
Get the correct spark plugs for your vintage Suzuki to solve poor running issues and ensure reliable starts.
- The standard recommended spark plug is the NGK B8ES, which is a reliable and affordable choice for most owners.
- For improved performance and longevity, consider upgrading to NGK BR8EIX iridium spark plugs.
- Replacing spark plugs is a very easy DIY job on the GS550T that requires minimal tools and time.
- Always check the spark plug gap before installation; it should be set between 0.7mm and 0.8mm.
Signs of Failing Spark Plugs on Your GS550T
Worn or fouled spark plugs can cause a number of noticeable problems. On a vintage bike like the GS550T, these symptoms can sometimes be mistaken for carburetor or other ignition issues. Since spark plugs are inexpensive and easy to change, they are often the best place to start your diagnosis.
- Hard Starting: The engine turns over but struggles to fire up, especially when cold.
- Rough Idle: The engine idles unevenly or vibrates more than usual.
- Poor Acceleration: The bike feels sluggish or hesitates when you twist the throttle.
- Engine Misfires: You might hear popping or sputtering sounds from the exhaust, particularly under load.
- Reduced Fuel Economy: You may notice you're visiting the gas station more often than before.
Check Other Systems First
On the GS550, issues like cracked intake manifold boots, dirty carburetors, or failing ignition coils can cause similar symptoms to bad spark plugs. Before replacing parts, inspect the intake boots for cracks and ensure your fuel is fresh.
Choosing the Right Aftermarket Spark Plugs
For the 1981 GS550T, you have two main types of aftermarket spark plugs to consider: standard copper and premium iridium. While Suzuki originally supplied plugs made by NGK, both NGK and Champion offer compatible options.
Brand Quality: NGK vs. Champion
For vintage Japanese motorcycles like the Suzuki GS series, NGK is the overwhelmingly preferred brand among mechanics and enthusiasts. They are known for their reliability and consistent performance right out of the box. Champion plugs are a functional alternative and will work, but most owners stick with NGK for peace of mind.
- Good (Standard Replacement): The NGK B8ES is the standard, non-resistor copper spark plug recommended for the GS550T. It provides reliable performance for daily riding and is very affordable. This is the go-to choice for most owners keeping their bike close to original specifications. The Champion equivalent is the N3C.
- Best (Performance Upgrade): The NGK BR8EIX is an iridium-tipped spark plug that offers significant benefits. Iridium is a much harder material than copper, allowing for a longer service life. These plugs provide a more consistent spark, which can lead to easier starting, a smoother idle, and slightly better throttle response. Note the 'R' in the part number signifies a resistor, which is designed to reduce electronic interference.
A Note on Resistor Plugs
Your bike's ignition system was designed for non-resistor plugs (like the B8ES). The spark plug caps may or may not have built-in resistors. Using a resistor plug with a resistor cap can weaken the spark. For a stock bike, the standard NGK B8ES is the safest and most reliable choice.
Cost of New Spark Plugs for a 1981 Suzuki GS550T
Replacing spark plugs is one of the most affordable maintenance jobs you can do. The total cost depends on whether you do it yourself and which type of plug you choose. Your motorcycle requires four plugs.
| Part Type | Cost Range (Set of 4) |
|---|---|
| New Aftermarket (Standard Copper) | $15 - $25 |
| New Aftermarket (Iridium) | $40 - $60 |
| Shop Labor | $45 - $90 |
Frequently Asked Questions
How often should I change the spark plugs on my GS550T?
For standard copper plugs like the NGK B8ES, it's a good practice to inspect them annually and replace them every 4,000 to 8,000 miles, or sooner if you notice performance issues. Iridium plugs can last much longer, often up to 20,000 miles or more.
Is it difficult to replace the spark plugs myself?
No, this is a very easy job for a DIY mechanic. Access to the plugs on the air-cooled GS550T engine is excellent. You will need a basic socket set with a dedicated spark plug socket. The entire job can typically be done in under 30 minutes.
What is the correct spark plug gap?
The recommended spark plug gap for the standard NGK B8ES is between 0.7mm and 0.8mm (about 0.028 inches). Always check the gap with a feeler gauge before installation, as they can be knocked out of adjustment during shipping.
Do I need to put anti-seize on the new plugs?
Modern NGK plugs have a special trivalent metal plating that acts as its own anti-seize and corrosion-resistant layer. Therefore, NGK does not recommend using additional anti-seize compound. If you do use it, you should reduce the tightening torque to avoid damaging the threads in the cylinder head.
Are there any recalls for the spark plugs on this motorcycle?
No, there are no recalls or technical service bulletins (TSBs) from Suzuki or the NHTSA related to the spark plugs for the 1981 GS550T.
Technical Specifications
OEM Part Numbers: 09482-00091
Thread Size: 14mm, Reach: 19mm (3/4"), Hex Size: 20.8mm (13/16"), Standard Gap: 0.7mm - 0.8mm, Required Quantity: 4
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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.
- Suzuki GS550T: