Iridium Spark Plugs - Kawasaki Ninja 250R Forum
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post #1 of 6 (permalink) Old 02-26-2013, 06:39 AM Thread Starter
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Iridium Spark Plugs

Some may have wondered or even been skeptical about whether or nor Iridium spark plugs offer any type of performance gains.
Questions such as "Are they any good?", "Are they durable?", "Are they worth the extra cost?" and "Do they improve mpg?", are common and rightfully so.

Many will say that good old standard copper/nickel plugs work fine for stock bike and fancy plugs won't do anything but make your wallet lighter. In some cases this may be absolutely true, but may be true for one bike may not be fact for all.

Well to answer some of those questions, I needed to find out for myself. Several things most will agree on is that, Iridium plugs will extend the interval between changing plugs, better idle, shorter warm ups, less energy used for ignitability and may not foul as much (compared to standard plugs), and may improve mpg. They also work better in higher compression engines and recommended for use with items such as the Takai Super Coils or other higher output ignitions. Also to note, Iridium plugs are now stock on the 400 & 650.

So, last month I replaced my spark plugs. I put in the NGK Iridium CR8EIX (pre-gapped right out the box, I checked). Got them at Advance Auto for $7.09 each. So far the plugs seems to make the bike run well. I can tell a difference in the bikes performance at higher rpms (above 8k) and slightly better idle. Start and warm up time seems to be better in the cooler weather as well (I ride year round). They seem to work nicely with the Pipercross filter & ethanol free gas I run. I guess overall they are burning the gas better which is indicated by the better throttle response. Although there is probably no big overall HP increase, power feels to be generated better. Now, all of this can be from the fact that I put new plugs in, but I don't think so. I ride and maintenance my bike enough to know the difference.

The other day I had a chance to ride in some low 70 degree weather. All I can say is that the cars on the interstate seemed to fall back quicker than normal. Was I going faster? Maybe. None the less, performance was overall better for this particular carbureted bike. For EFI engines, the performance may be different, they may or may not see any change at all (IDK), but for the Ninja 250 and the rich top end, this plug may offer the benefit of better combustion.

I liked these new plugs so much, I bought a second set. They happened to be on sale for $6.09 each. It'll be a while before I change plugs again, but you never know. For $7 more than I would pay for a set of standard plugs, I got a small bump in performance and an extended change interval. Not bad considering some spend hundreds for things like slip on exhaust for a small boost and noise.

I'll see how they run when the weather starts getting much warmer. I have a feeling I won't be disappointed.
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post #2 of 6 (permalink) Old 02-26-2013, 02:24 PM
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Re: Iridium Spark Plugs

What year is your bike?
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post #3 of 6 (permalink) Old 02-26-2013, 04:28 PM Thread Starter
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Originally Posted by importeclipse420a View Post
what year is your bike?

It's a 2009.
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post #4 of 6 (permalink) Old 03-24-2014, 11:42 AM Thread Starter
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Here's a response from another rider and his experience with Iridium plugs in his Ninja 250.

." testing was similar to yours. Take it for what it's worth but I bought two sets of plugs, standard and iridium both NGK. I put in a brand new set of standard drove for one tank of fuel back and forth to work for a couple weeks.

Next tank swapped out brand new plugs for iridium. Thought to myself... they are still new, I will throw them back in after I use and prove iridium don't make a difference. Noticed an immediate difference in idle and throttle response from the brand new plugs I had in there. Next tank showed mileage improvements back and forth to work. I know it's neither here or there, questionable testing but the difference was enough to notice and the mileage changes have been consistent. Not turning back and unfortunately these nickle plugs are gonna stay on the bench.

I too have to give the nod to iridiums, even if it is only seat of the pants feel. Shrug. take it all for what it's worth. "
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post #5 of 6 (permalink) Old 03-25-2014, 02:26 PM
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I think i will try a set out on my 250. It has 5,700 miles. So its about time to do it.

sent from my fone.
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post #6 of 6 (permalink) Old 10-18-2014, 08:54 AM
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HI guys - thanks very much for posting this info.

Last edited by Apple91; 10-19-2014 at 02:11 PM.
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