2003 FLSTC softail. Going to try Accel Copper in my 2003 Her. Not sure if I should gap them at .040" or what. Also, not sure how long the old plugs have been in the bike. Should I hit the base of the installed plus with a little BP Blaster to help in removal?

 

If you got an Accel plug that is the equivalent to the OEM plugs, then use the gap stated in the manual, .038" to .042"..... i always shoot for .040"

If you changed plug heat range, or other characteristics... you're on your own...

Not sure why you want to use Accel plugs, but be advised, there are some aftermarket plugs that will not work well with the Ion Sensing technology that HD uses for spark knock during the Twin Cam years...

I only use the OEM plugs #6R12 or Champion Copper Plus, #810 / RA8HC plugs...

I don't use the iridium, or other exotic spark plugs... the Champion Copper Plus plugs work very well, and are both cheap and easy to change out... I change them frequently... regardless of mileage, I usually change them at 2 years... cheap & easy insurance...

If the plugs look corroded around the bases, can't hurt to hit'em with PB blaster, just no need to get crazy and have it running down the side of the engine...

While I have a can of PB Blaster on hand, I prefer Kroil oil...

Good luck with your plug change...

 

I don't think his 2003 has a spark knock sensor. (I run NGK's (because that's what the guy at NAPA had in stock for my '02,) at .040" too.

 

Good point....but I don't think he mentioned if he was carb or EFI.....

If he has a carb, I would agree...

But I believe the Ion Sensing Technology was introduced with the Delphi ECM on softails in 2001 and all other EFI bikes in 2002....

Stolen form an article dated 2002, about the advantages of the new Delphi ECM:

"Ion Sensing System - this system uses ion-sensing technology to detect detonation or engine misfire in either the front or rear cylinder by monitoring the electrical energy at the spark plug following every timed spark. If an abnormal level of energy is detected across 2 or 3 spark firings the ECM responds by retarding spark timing in the problem cylinder as needed to eliminate it."

 

If you drive it in the mountains or the least bit hard, there's a good chance it will ping. My 2004 does with NGK even on an upgrade on pretty level roads in 5th at 55 if I don't get 4th.

The resistance on a car plug it twice what the Harley branded plug is.

There was an engineer on here who said that should not matter. Was close enough. Over my head.

 

 

The "branded" HD plug is made by Champion (btw.)

 

Hat....How do you feel about the SE Plugs?

 

Don't know... never used them.. I go with OEM HD plugs or Champion...

The SE 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."

IMHO, that's overkill at a premium price ($20.00 each) for a plug that is easily changed and otherwise pretty cheap. I check and change them frequently, so I don't need the "long-life" factor with the expensive exotic metal plugs. I can change one Champion plug four times for the cost of one SE Plug....

Also, IMHO, a lot of the "special design features" in most premium plugs that claim to affect the "flame propagation" and/or fuel burn, may make a difference in a racing, high RPM, high compression, high HP engine... But on a street driven bike... I don't think there's an advantage.

My 124" Crate engine from FuelMoto that dyno'd at 135HP & 151TQ uses two Champion plugs costing $3.95 each. That's what FuelMoto put in the engine and tuned it with...


NOTE:
I will offer one caveat to the high performance, long life plugs offered... My Jeep recommends a 100,000 mile plug change interval. You need to pull the intake manual to replace one bank of plugs on that engine... I'll certainly pay a premium for long life plugs in that application...

So, if someone doesn't realize how easily the fuel tank is removed on an M8 to change out all 4 plugs, or they don't do their own maintenance and have to pay a shop to change out their plugs... A platinum or Iridium plug for long life may be worth it to them...

 

Thanks Hat, some real solid advice here, I know you've got your **** together when it comes to the mechanics, just wish I knew a 10th of what you forgot. lol

Looks like I'm going Champion this year instead of the SE's.

Thanks again.