I have had good luck with NGK Spark Plugs and ACCEL Spark Plugs also. I prefer the ACCEL if I can get them but it also depends on the bike I'm riding. My Wide Glide is EFI so I leave the spark plugs and wires stock, the ECM takes readings on the plugs and wires for resistance and does it's anti knock advance accordingly. If you change the resistance the bike runs fine but will act up at times. I have personally verified this with three different plug/wire combos and got the same results everytime. The bike would intermittantly go into high idle when the bike was hot or sometimes it wouldn't even start correctly with these combos. It's all personal preference but with EFI I'd say stick with the Motor Company, non EFI, go with ACCEL or NGK.

 

I had good success with champions which are copper core. This site has all the different ones for all the different motors

http://www.nightrider.com/biketech/hdsparkplugs01.htm

 

Nothin' wrong with the stockers, but Champion (RA8HC) or Autolite (4164) are cheaper and work just as well. Nothing any fancier or more expensive has been proven to be any better. No. Nothing.

 

Nothin' wrong with the stockers, but Champion (RA8HC) or Autolite (4164) are cheaper and work just as well. Nothing any fancier or more expensive has been proven to be any better. No. Nothing.

Ahh, very good DT! Of course, someone will find your theory flawed because they won't have to pay $15 a pair for the Champs or Autolites. Damn, if they ain't expensive they can't be any good for a Harley!
Here's what we do here. Autolite 4164's for 10 to 1 compression or less. 4163's for over 10 to 1. About a buck fifty a piece. 99 cents on sale sometime. EFI or carb.
I know, no way they can compare to the Screamin' Eagle plugs.

 

The nightrider site always proves to have useful info.

 

I second Grock, and any auto parts store has them....Thats what i been using for a while now.......

 

i went to the ngk DCPR7E and the bike runs great (02 fxst-carb). FYI: bike shops want 4 to 5 bucks for them, i got them from Advance Auto Parts for 1.98.:banana: :cheers:

 

Autolite 4164's

Running them for over 20K miles - work perfect!

 

You gotta carry an Autolite plug wrench with ya. That would be an 11/16 deep socket. Why do they make them in that oddball size?

 

Follow Up...

You gotta carry an Autolite plug wrench with ya. That would be an 11/16 deep socket. Why do they make them in that oddball size?

Yeah, that's weird about the Autolite size thing. Smaller thread diameter than standard automotive plugs (12mm vs. 14mm) and yet a larger hex (11/16" vs. 5/8").

Anywayz--as a follow up to my previous inquiry, Both Champion and Autolite make a "standard" and a "colder" plug for Harleys (Twinkies, that is):

Champion: RA8HC--Standard heat range
RA6HC--Colder

Autolite: 4164--Standard heat range
4163--Colder

I am amazed that I can still see production inconsistencies in Champion plugs. Center-electrode protrusion is not the same on all plugs (even when comparing plugs with the exact same part number), as-packaged gap can be off by more than .020" from one plug to the next, and the center electrodes often look crooked. Amazing that the MoCo even uses their ****...

-Fat

 

Back 100 or so year ago everyone in my home town always ran a plug that was one temperature range colder than stock in the summer. I don't know why we did that but everyone in our group of about 40 riders ran the colder plugs. I think it was an old wives tale that the engine would run better with the colder plugs. Now I just run the Autolite 4164s all year long.

Would running one temperature range be of any benefit in hot azz Houston or in the summer months anywhere?

 

I second Grock, and any auto parts store has them...

Godfrey friggin' Daniels....Not only does my local AutoZone not have 20W-50 Mobil 1...or any motorcycle oil for that matter, they don't carry Autolite 4164's either. :nunu:

Worthless as boobs on a boar.

 

Yeah, that's weird about the Autolite size thing. Smaller thread diameter than standard automotive plugs (12mm vs. 14mm) and yet a larger hex (11/16" vs. 5/8").

Anywayz--as a follow up to my previous inquiry, Both Champion and Autolite make a "standard" and a "colder" plug for Harleys (Twinkies, that is):

Champion: RA8HC--Standard heat range
RA6HC--Colder

Autolite: 4164--Standard heat range
4163--Colder

I am amazed that I can still see production inconsistencies in Champion plugs. Center-electrode protrusion is not the same on all plugs (even when comparing plugs with the exact same part number), as-packaged gap can be off by more than .020" from one plug to the next, and the center electrodes often look crooked. Amazing that the MoCo even uses their ****...

-Fat

I just went through 5 sets of Autolite 4164's and they are having some pretty significant quality issues. Highly varying center electrode heights by 0.030" or so, also weak welds on the ground strap. Went to gap a pair that the center electrodes looked alright on and barely touched the ground strap to open the gap slightly and it popped off. Bad weld.

 

If you're determined to buy something different, I would suggest getting something in the same heat-range, making sure that it is gapped correctly.

Beyond that, I would get something that comes in a nice looking box.

Once you get a good, fat spark that is capable of igniting the air/fuel mixture at the correct time, you can sit back, have a cold one and admire the nice designs on the packaging.

 

If you have an EFI bike, stick with the harley plugs, because a lot of readings come via the sparkplugs and the wrong kind can cause a check engine light. I know because this happened when I went with a screaming eagle splitfire plug. The check engine light came on with the code" no combustion"

Switched back to the harley platinum and the light went away

 

The only "trouble" I ever had was with some brand other than H-D stockers. Started the bike and it was running on one cylinder??? Lucky for me I was at the H-D shop

 

I just put the SE platinum tip plugs in my stock 88B. Seems to run a bit smoother. Fortunately, I didn't have to pay for these, and they are expensive, $15 per pair. The stock plugs only had 1,400 miles on them, and looked good, dry and grey. Which is surprising since I know it's running lean, but maybe they should look that way in this condition. I wouldn't attribute a check engine light with just a change in spark plugs.

 

So whats the point in paying top dollar for platinum or really expensive silver plugs?? Copper, plat, silver? Does it really matter?

And Iridium?? Isn't that on oakley sunglasses??

 

The main advantage to platinum plugs is longevity. A good platinum plug in most newer autos these days has an average life of 100,000 miles. Matter of fact, alot of manufacturers don't recommend a plug change in the owners manual until 100k. On a properly tuned engine they do last that long. I've pulled platinums out of a 98 F150 5.4L with a 100k on them and they still looked good.