So I thought I would ask some of you guys that are more motor builder/gear heads than I am, what you think. When I bought my '17 RK, I had the dealer put the SE Stage IV Kit in it so it's covered under the 5 year warranty plan I bought. After they finished the build, I asked what plugs they put in it. They said the stock HD Plugs would be fine for that motor. The reason I question that is because when I had a local race builder tune my '03 RK with a Stage III Kit in it, he told me that he changed out my old plugs to a set of colder plugs because of the BB Kit and Cams. (I'm almost positive he said colder..... they are Autolite 4162 plugs). It makes sense to me that you would want to run a different plug other than stock on a non-stock motor. Anyhow, would you run just stock plugs in my motor or something else? I already know about the "Oil Thread-esque" debate over regular spark plugs vs Iridium vs something else, and that's not what I'm asking about. Just wondering about hotter vs colder vs stock in this application. Thanks for the input fellers.

 

Nothing???........ Anybody????

 

sounds like HD recommends these..give em' a try and let us know how they work

https://www.harley-davidson.com/stor...on-spark-plugs
Screamin’ Eagle® Performance Spark Plugs feature double platinum coating for superior erosion resistance and extended life. The “V” trimmed ground electrode reduces shrouding of the flame front to promote flame propagation, and the fine wire center electrode enhances startups and ignitability.
For High Compression Applications
Feature Ribbed Core Technology (RCT) that provides resistance to fouling
Designed with Original Equipment-style noise suppression to prevent electrical interference with radios and CB communication equipment
Works great in racing applications where rich air/fuel conditions are required
Designed for high performance applications involving modifications in high-flow air cleaners, camshafts, exhaust, performance heads, ignition components, higher compression ratios above OE configurations or engines specific for racing applications

 

Hahaha.... now I feel like a total dumbass! I was thinkin this needed to be some cool freakin plug from some exoctic motor shop...... Didn't think to search HD's SE Performance section! And it the SE Stage IV kit, sooooo..........yeah. DOH!!! Thanks MJ...... I thinks will probably do the trick.

 

CRAP!!!! They don't fit the M8's!!!!Damnittohell!

Edit: But these do......

https://www.harley-davidson.com/stor...on-spark-plugs

And Ribbed Core Technology for her pleasure!

 

just run the OEMs then, if it runs great then you're good..seems a lot of people that swapped for the SE's in the past weren't impressed and swapped back anyway, for mild builds anyway..since Harley doesn't make them for M8's even with their SE builds then can presume they didn't think they are necessary I suppose...they may offer ones in future product releases..might be worth checking the 2017 P&A and SE Catalogs too..the Online Store isn't always accurate, up to date and reliable..they could exist

 

Sorry man, I was in a hurry to get to bed when I edited that last post and I wasn't as clear as I should have been. I DID find the SE Plugs for the M8. Just had to do a search on the HD site under our bike, not just the standard SE Plug.

https://redirect.viglink.com/?format...on-spark-plugs

I'm not looking to gain any performance, (HP or TQ), out of these plugs, so I won't be disappointed by not being able to shave a full 1 second off of my 1/4 mile track time or anything. I'll try them once and see what happens. I have noticed a little pinging on really hot days, 100+, while riding 2 up on an uphill grade. We have real gas out this way but I have thought about dumping just a little Octane Booster in the tank a few time to see if that will help with the pinging. I guess I'm just playing around with the only thing I can play around with, as far as the motor build. I'm not going to touch anything on this motor until my 5 year warranty is up........ then it's play time!

 

cool..I saw those SE's for the M8, they say for Standard Compression as opposed to the ones that are for Higher Compression that don't fit M8's..who knows..guess just try them..bet the OEM's will work fine as a 'contingency plan'

 

From a tuners POV the purpose of the sparkplug is to effectively ignite the air/fuel mixture in the combustion...period.
The new M8s use 2 sparkplugs per cylinder so ignition is covered.
So there is no need to buy anymore than stock plugs because there will be no benefits or gains from buying different, more costly ones.
The above is my opinion based on my experiences tuning bikes and back to back sparkplug tests of virtually every plug claiming to be better than stock.
If you have enough mid-rpm cylinder pressure one heat range colder plug than stock MAY help with high heat/load detonation (pinging, rattling, etc).

Bob

 

I'm thinkin' maybe put the $40 into my "Slutty *** Chrome Parts" Jar and quit trippin' on these plugs.......... there's always chrome bits and pieces that need to be bought, lol!