Denso iridium plugs?
Believe me, I've tried most of them and I can assure you they make zero difference on a Harley. You will also not find any independent testing that shows any difference whatsoever on a dyno.
In fact, you have to be careful with modern Harleys (07+)
because they have an anti-knock system that can be disabled by non-stock plugs.
So you can spend a lot of money on zero improvement and damage you engine in the
bargain. Yup, money well spent. Not.
In fact, you have to be careful with modern Harleys (07+)
because they have an anti-knock system that can be disabled by non-stock plugs.
So you can spend a lot of money on zero improvement and damage you engine in the
bargain. Yup, money well spent. Not.
This info is the only reason I will even buy Harley plugs. It's it worth the risk over a few dollars. Have you ever seen a piston after detonation has occurred.
Road Captain
Joined: Jan 2012
Posts: 710
Likes: 2
From: San Bruno
so do these non-stock plugs include the HD screaming eagle plugs or whatever they are? because although they are HD plugs, their considered "performance" plugs which wouldnt make them stock. would they then effect this anti-knock system?
Road Captain
Joined: Jan 2012
Posts: 710
Likes: 2
From: San Bruno
not to mention, when you change the gap you change the spark. and the manual gives you a range of gaps if i remember correctly. i believe .037 to .045 or something like that. so unless you have your gap at the factory setting, wouldnt the knock sensor not function properly because of the change in the gap and spark?
Road Warrior
Joined: May 2012
Posts: 1,570
Likes: 117
From: Southeast NC
they work. they are not meant to increase hp. they are meant to last longer and change the shape of the spark due to the thinner electrode for a little bit more efficiency. Are they worth the extra 10 bucks apiece? Probably depends on if u are one of those guys who put walmart oil in your 25 thousand buck bike instead of name brand oil. You just spent 25 k on your bike and yur gonna put cheap plugs and cheap oil in your pride and joy. Even if they dont work any better, if i have piece of mind that i put the best in my bike, spark plugs, oil, tires, ect, then im good with that. i have no intention of penny pinching on hardware for my bike. It sounds like some guys take pride in the fact that they saved 20 bucks on plugs and put cheap 1.95 plugs in one of the biggest investments in there life. go figure. im stumped
Road Warrior
Joined: Apr 2010
Posts: 1,739
Likes: 10
From: Suffolk, England
they work. they are not meant to increase hp. they are meant to last longer and change the shape of the spark due to the thinner electrode for a little bit more efficiency. Are they worth the extra 10 bucks apiece? Probably depends on if u are one of those guys who put walmart oil in your 25 thousand buck bike instead of name brand oil. You just spent 25 k on your bike and yur gonna put cheap plugs and cheap oil in your pride and joy. Even if they dont work any better, if i have piece of mind that i put the best in my bike, spark plugs, oil, tires, ect, then im good with that. i have no intention of penny pinching on hardware for my bike. It sounds like some guys take pride in the fact that they saved 20 bucks on plugs and put cheap 1.95 plugs in one of the biggest investments in there life. go figure. im stumped
This is pretty important these days with the crap fuel that's sold and the bikes being tuned to meet ever tighter EPA standards. So there's more chance these days of intermittent knocking. Not enough that its even noticeable to the rider but its going on and without anti-knock it could lead to a reduction in engine life.
People will put stupid-grade oil in their engine to apparently extend its life but are willing to risk real engine damage by sticking in odd plugs. It don't add up to me.
Don't trust my opinion? How about Fuel Moto's?...https://www.hdforums.com/forum/fuel-...ark-plugs.html
Road Captain
Joined: Aug 2009
Posts: 513
Likes: 0
From: Utah
I hear allot about the anti knock system but also see allot of post on the 96" and larger engines pinging bone stock. The anti knock system is not all that impressive in my book. I think it is the tune that keeps it from knocking.
Tourer
Joined: Jun 2011
Posts: 499
Likes: 1
From: Herrin, Illinois
they work. they are not meant to increase hp. they are meant to last longer and change the shape of the spark due to the thinner electrode for a little bit more efficiency. Are they worth the extra 10 bucks apiece? Probably depends on if u are one of those guys who put walmart oil in your 25 thousand buck bike instead of name brand oil. You just spent 25 k on your bike and yur gonna put cheap plugs and cheap oil in your pride and joy. Even if they dont work any better, if i have piece of mind that i put the best in my bike, spark plugs, oil, tires, ect, then im good with that. i have no intention of penny pinching on hardware for my bike. It sounds like some guys take pride in the fact that they saved 20 bucks on plugs and put cheap 1.95 plugs in one of the biggest investments in there life. go figure. im stumped
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Road Warrior
Joined: May 2012
Posts: 1,570
Likes: 117
From: Southeast NC
would u put cheap brake pads, rotors and brake fluid in your 800 lb harley to save a couple bucks? not me. spend the extra 10 bucks apiece on some nice screamin eagle spark plugs. come on. u know u want to. u can do it. just release the money from yur paws...