NGK Iridium IX DCPR7EIX Spark Plugs: Harley Davidson Twin Cam (Pair) - 1999-2016 Model Years Review

Great spark plug, works great on my '09 Harley. BE CAREFUL WHEN DISCONNECTING! Gone are the old days of using the center electrode as a lever with a screwdriver or slit to open the slit a bit. Using pliers, grasp the side electrode (hand) and bend it.

Is this a joke? Just got my "NGK" spark plugs in the mail. You are not NGK. They are not trademarks of DENSO REPLICAS. THEY HAVE RUSSIAN, JAPANESE AND SPANISH all on the box. They pointed to "DENSO" like I was a fool. I don't know how or what happened from all the reviews but that sucks

Worst spark plugs. I have always used NGK on my dirt bikes and on my boat. Put it in my Harley Elctra Glide Classic and it pops out on start up. The strength seems to have diminished. I reinstalled my Harley Davidson spark plugs. They had 8000 miles on them. The bike became smooth and rode normally. No pop at startup. The release on the NGK was ok.

I have just fitted these to my Harley and am very impressed! Starts immediately, pulls soft and hard! I used them on my 103 before and they weren't any different from the 6R12, but now I have an S&S 124". Now it's very different. My new engine responded really well to these plugs. Oh, and as for the gaps The packaging doesn't even say DO NOT HEAL THESE PLUG I have used SE plugs and 6R12PP plugs and these NGK plugs are the best in my opinion.

Purchased after installing the first stage of the update. Vance and Hines 3" Double Oblique Pads, Arlenness Large Suction Cup Air Cleaner and Vance and Hines FP3. I received an engine code when one of the cylinders was running enriched, after many unsuccessful attempts to run the FP3 autotune function I decided To install them and no enriched code has run since then I suspect it's a bit hotter fork than stock HDs Very happy with them

I inherited a 2000 Dyna Super Glide from my late brother when he died five years ago. Unfortunately, the bike has been in my little brother's garage ever since. Long story. But it's time. So I have a job. And traffic jams were critical. I trust NGK. I use them in all my cars. The price doesn't bite here. Plugged it in with a new battery and the bike immediately caught fire. I still have a lot of work to do, but I will get this bike back on the road where it belongs. I owe that to my brother. I…

2002 HD Heritage Softail. I never believed that simply changing the spark plugs would significantly improve gas mileage, but I've seen a 10-15% increase with these plugs with no noticeable loss of power. And it's not just from replacing old spark plugs, I've been monitoring my MPG since I bought the bike and I'm seeing a 4-7 MPG improvement since installing the NGK. Lowest mileage I've had after battling 50+ mph winds all day, best was on a mountain cruise, but every tank of gas was better than

So I randomly chose .032 as Harley claims, Low - Road King, test drive. The bike was sharp, like a wobbly bike, but obviously with the wrong spacing. I wanted to go back but changed to .040 inch, not metric btw. And now it works like a factory. Everything seems fine, no real improvements but it's fine so I'd say it's a good OEM replacement but I'll just buy a branded Harley next time. And yes, I think they were distributed correctly out of the box. I messed it up by pinching the bottom end of…

These spark plugs banged on the seat for 1000 miles then my bike ran lean and started having spark knock issues. I measured the resistance and it is 4.3k ohms, standard candles measure 12.4k ohms. I put the original spark plugs back in and the spark knock and engine codes are gone. I have a 2004 HD fxstdi with an open loop system and these spark plugs were causing problems as the change in resistance after detonation is measured by the computer and causes it to tilt and go into safe mode. Not…