I tried a few different ones, champs, accel, SE, never had bad results. When I had Hillside port my heads, I asked them and they recommended to run NGK BRP5ES-11 @.35

 

over the years i have used LOTS of different plugs in the HD vTwins
my experience shows that if the bike is stock or close to it, the OEM, Champion or NGK all workvery well, good enough not to entertain thoughts of anything else.
the only time to use the OEM is with Delphi FI, people are gonna say I'm not correct, dont care, they dont have my training or experience to back it up.
on the older carbed bikes NGK's work very well and the are LOTS of heat ranges ot work with.
other people have their opinions, this is mine.
m

 

And they suck because they're make to Harley specs not to Champion specs. Champs are great on Shovelhead but not Evo's.

 

My 93 Heritage Classic likes Autolite plugs best.

 

If anyone would like to experiment, here’s a test.

‘’Take your favorite plug, say Champion. Set the gap to 35 thou. Run about a 1/4 of a mile wide open and see if it cuts out, if good gap them at 38 thou and repeat.. if good go to 40 thou, then 45 thou, then 50 thou.. find out when under a load it cuts out.

‘’Then try another brand and do the same. You can do this with coils too. You’ll find two of the same brand won’t handle the load the same.

I gapped my 93” 11.97:1 mechanical compression shovel at 50 to 55 thou for a big fat glorious clean burning spark. With the right coil and plugs clear into 6K+ it would hold that clean fat spark. This is why I personally like Autolite.

Try for yourself… maybe your results will be different.

 

I actually have done this test on the dyno, the ngk wasvthe best and autolite was the worst.
all in the same bike, with different gaps, on a stock coil, the on more hot rod coils.
m

 

Interesting we get completely different conclusive results. I didn’t find NGK to be bad, I just didn’t find them to be better and to be way more expensive. Not to mention I couldn’t get the heat ranges especially with the short reach plugs. Autolite has consistently proven best. I drag raced Hot Street and Vintage Street from 2000-2003. These were intense years with lots of time spent dedicated to going fast and investing time and money formulating opinions. Health took me out for a number of years now I’m back and am trying new things going EVO.

I’ve street tuned a bit, done a bit of indexing and plug reading to dial in the carb, timing and gearing but I as of yet have no track time or dyno time. Tough to have the open road without a clock to quantify on the street. I was scheduled for a full day to dyno but it had to be temporarily cancelled. Hopefully soon I’ll get in my dyno tuning.. he already knows I’m about 3k-6K for broadest highest average for torque & ponies. He already knows we’re switching carbs and pipes. Whatever combo is superior I’ll take to the track and retune for highest mph. I have a journey ahead. I believe in Autolite due to my past experience, but I suppose the EVO chamber may respond differently from my Shovel knowledge. I’m already venturing out with ignition.. with Shovel all the fancy coils and ignitions disappointed me under heat/load compared to the late 90’s stock Harley softail single fire coil and the DynaS.. but here I am with a Dyna2000i and a Crane Hi4 to try…. We shall see.

I have no clue why you say Autolite was the worst, I find that completely opposite from everything I know as fact. Magaro is Running Autolite in both his street bikes with 130 tires FXE 9.80’s, FXR 10.70’s.. Greg Dahl is running Autolite…

I checked Cycle-Rama out due to your posts. You guys have some really big number dyno sheets shared on your site. Sounds like you have a great reputation. Don’t know if it’s the “more than one way to skin a cat” or there is an alternate universe.. do you have any clients who race? That’s not a knock or dig.. I’m sincerely curious if you have clientele who race. Would love to see time slips… maybe even know some names. You guys are right here near me. Would be a great resource. Course does look like you’re focused on M8 only? I’m likely done with EVO and will likely never move forward. I just like the EVO & Shovel bikes. I use a computer all day… don’t ever want to have to use a computer with my bikes. I like the limitations of Carburetors.

 

i have no relationship in any way shape or form with Cycle Rama. they are another and different entity than me.
please feel free to PM me and i can explain in more detail.
the one thing that i can say is that the Evo and TwinCam bikes are a completely different kettle of fish than a shovel. All of your thought processes apply, just getting there is a bit different.
m

 

...

 

Accepting the fact that plug choice seems very subjective, has anyone tried e3 plugs on their evo? I'm due for a plug change and am just curious if their weird design is snake oil or functional. Any danger in using them?