5308 Spark Plug

This Denso spark plug was a definite welcome addition to my Harley. Starts alot easier and faster, better horsepower because of a better and more efficient burn in the cylinders now. haven't checked fuel mileage yet but I imagine it will go up a couple mpg. I am totally pleased with the purchase. I like these better than the NGK plugs. Don

I wish I could say I put these on and they worked great, however they did not fit my application as the “fit tool” on Amazon said they would. I begin with the return process through Amazon to find that I would have to pay nearly half the price of the product to return them. Totally not worth it, that’s money out of my pocket for Amazons mistake, not mine nor the sellers. I could understand if the Amazon fit tool told me that it wasn’t a fit and I bought it anyway only to find it not to fit, then yeah sure I would foot the bill for that.

Even though the cataloging of Amazon's related parts for my Harley Davidson Sportster said that these plugs did not fit my motorcycle, THEY DO. By using other web sites I found that these do fit and work well. I noticed a improvement right away in the performance of my bike. Quicker acceleration and the engine runs smoother. I have Iridium in two other vehicles and noticed the same thing and they last longer.

These plugs are a little exspensive but make a smoother power delivery on my Sporty !!Very small electrode which should not be gapped, it is good to go as is .I did notice the bike runs cooler with these sparks installed .... Yeah !

Had the plugs in for 17,000 miles. Just pulled one to check; no sign of wear. I don't necessarily believe the claims that the plugs will get better mileage or power; I THINK my mileage went up a little. But they LAST. If you're going to keep your car for its lifetime you should save money with Iridium.

Installed these myself in my motorcycle. Sounds great, runs great. We'll see how long they last, but so far, so good.

These plugs function properly in a 2003 Harley Davidson twin cam 88B motor. Smooth operation and slightly quicker starts. No difference in fuel mileage. No audible pinging either.

I want to use iridium plugs on everything and I think Denso makes the best. If I can't get them, I'll go with NGK. Amazon price make it easy not to run down to the auto parts store. And no tax!!!!!!