View Full Version : Spark Plugs

02-22-2007, 02:38 PM
I am new to this Buell site - cool stuff!!
I have a 03 Firebolt XB9R with the race kit.
I need to replace the plugs and thought that someone on the sight may have a good idea what are the best plugs.
Thanks in advance for your help.

02-22-2007, 04:14 PM
Stick to the stock plugs from the dealer. every time I have put anything but stock plugs in any Buell it has been a comeback. Anything from missing at idle, pinging, hesitation, you name it. My advice is stick to stock. I have the same bike with a race kit and run stock plugs. Only thing is I change plugs every 5000 miles just because they are cheap.

02-22-2007, 04:19 PM
BPG is right on, the downsides of fancy plugs outweigh the possible claimed gains. Welcome to Buellxb.com!

02-22-2007, 06:40 PM
Thanks guys, I will stick with the stock plugs. Just double-checking the number, 10R12A, correct?

02-22-2007, 07:21 PM
Thats right... [up]

03-03-2007, 01:14 AM
ok folks, After 3plus years of kicking buell tires, I just purchased a '07 Black XB12R. She is pretty however, whats with the rear license plate? Any1 know of a trick kit? Also ........ What would you recommend for performance upgrades? I would think that the ppl on this site know what works and what products I should stay away from. Thanks folks, I am proud to ride my American Sportbike.........
SGT. Todd Heimer

03-03-2007, 01:24 AM
Once again, I thinking this is the fourth time I have referred someone to my post of the undertail I did. lol check it out. its under do it yourself mods.

03-04-2007, 11:37 PM
thanks BuellPartsguy, this is on the second time that I have been on this site.

03-05-2007, 01:32 AM
I know I am just playing with ya. No big deal man. lol :p

10-09-2007, 02:49 AM
I have an 08 XB12R. Just did my 1000k service myself and went with NGK Plugs. Have never been a big fan of Champion Plugs. My bike is stock and it is not recomended until 10,000k. So far haven't noticed any difference with the performance. If I new what a bitch it was going to be changing them out, I would have waited until 10,000k.

10-10-2007, 12:43 AM
My bike is going in tomorrow for the 10k check up.....I have the service manual to tell me how to do everything. Now I just need to get the right tools to do everythin......[sad][confused]

02-10-2010, 10:18 PM
08+ Spark plugs: HD# 10R12X, Champion# RAX94YC, NGK# DPR8EA-9 (stock temp) DPR9EA-9 (colder plug).

02-10-2010, 11:55 PM
DCPR9EIX Iridiums

02-11-2010, 01:45 AM
7mary... so for an 08 TT
wanting irids...
DCPR9EIX Iridiums

02-11-2010, 02:30 PM
Yes, - it's DCPR9EIX for your '08 TT.

04-03-2011, 12:51 PM
Anyone know what plugs are for a 2009 XB12XT?
I don't want stock plugs.

04-03-2011, 10:16 PM
All XB's are the same - I'm partial to the NGK Iridiums (DCPR9EIX).

04-03-2011, 10:19 PM
I was a Oriellys the other day and it said that my bike 2010 XB12Ss called for DCPR8EIX I know that they are the same plug just different heat rating, but do some call for the 9 and others the 8. I think the difference between the plugs is the gap. the DCPR9EIX that I got had a bigger gap than what the DCPR8EIX called for.

Jobe Zeebuh
04-03-2011, 10:24 PM
NGK Iridiums (DCPR9EIX).

Bam! That is what I run as well. Iridium is cool technology!

Q. Where does Iridium come from?
A. Fifty million years ago, an asteroid composed almost entirely of the precious metal Iridium (Ir-77) struck the earth, creating the Gulf of Mexico. The resulting dust cloud destroyed most living things and ended the dinosaurs reign on earth.

Q. Why was Iridium not used until today?
A. The extreme strength of the metal inhibited its large-scale usage in spark plugs. However, through recent technological advances, DENSO has harnessed the power of Iridium. DENSO’s patented alloy is composed of iridium, complemented by rhodium (an even stronger metal). The rhodium is added to increase oxidation and wear resistance. DENSO was able to make this durable alloy workable by pioneering and patenting a Laser-Welding/process. This process provides a 360-degree weld so reliable that the electrode resists wear, even in the harshest conditions.

Q. What makes Iridium better?
A. Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world’s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.

Q. How long will Iridium Last?
A. Iridium use represents the most significant technological advance in automotive spark plug manufacturing, since platinum was introduced in the early eighties. As vehicle manufacturers produce increasingly complex and efficient automobiles, there is a greater need for long-life plugs that can tolerate leaner fuel mixtures and improved combustion processes.

Q. Why is the U-Groove special?
A. The patented U-Groove allows the flame kernel to fill the gap formed by the U. This ball of fire develops a larger and hotter flash front a complete combustion. The flat ground electrode design of ordinary spark plugs crush the spark, inhibiting its growth; this effect is known as a “quenching effect.” The simple, but efficient, U-Groove feature results in better fuel efficiency, improved throttle response, and greater firing energy.

Q. Why are there different heat ranges? Which one should I use?
A. Part of your spark plug’s responsibilities, in addition to firing a spark, is to remove heat from the combustion chamber. This is accomplished by channeling the heat through the insulator material and metal housing. From there, the heat is transferred to the cylinder head where the engine cooling system can go to work. A spark plug’s heat range is its ability to dissipate heat. The “colder” the plug, the more heat it can channel out of the combustion chamber. In a performance application, colder heat ranges may be necessary to handle the extreme temperatures brought on by higher compression ratios, forced induction, and high RPM’s. While “Colder” plugs may seem to be the way to go, please remember that the spark plug must achieve its “self-cleaning” temperature where it can burn off fuel and carbon deposits. Otherwise, the plug could “foul out” where it is prone to misfiring and poor acceleration. A plug that is too “hot” can overheat, also causing power loss, detonation, pre-ignition, and possible engine damage. A good, general rule of thumb is to start with the factory recommended heat range. For every 75 to 100 hp you add to your engine, you may go to the next colder step.

Q. What torque recommendations do you give for the Iridium plugs?
A. Improper installation may cause poor performance and could result in costly engine damage.

Q. What kind of performance will I get from this plug?
A. Generally, you do not purchase spark plugs for performance enhancement. While Iridium Power spark plugs have contributed to numerous accomplishments through dyno-testing and actual use, their true benefit lies in their efficiency, durability, and improved firing power. Serious tuners modify their vehicles by increasing boost through turbo-chargers, super-chargers, and Nitrous. They are also known to add high-energy ignition systems, tinker with timing, adjust fuel mixture ratios, and increase horsepower through other means. Putting these kinds of demands on their engine increases the need for an efficient, durable spark plug that can handle these kind of harsh environments. That’s where Iridium Power can make a major difference.

Q. What kind of testing has been done?
A. Iridium Power has been tested in many arenas. The most common area of testing has been on the track. There are currently many people using the plugs in import drag racing, with results being quite favorable. Some racers have seen E.T.’s decrease by a tenth and less fuel consumption during a pass. Circle track racers using the plugs notice better acceleration coming out of corners and more consistent idling. The other area where the plugs have been tested are on good old dynos. The results have indicated horsepower increases over stock plugs of 2-3 Hp in a naturally aspirated engine and 27 Hp in a supercharged/turbocharged engine as seen in the January 2003 issue of 5.0 Mustang & Super Fords magazine*.

Q. How do I gap Iridium plugs
A. Before attempting to gap any Iridium Power spark plug, please review the specification chart to see the factory-preset gap. In most cases your Iridium Power plugs do not need to be gapped. Even with small variations in the factory set gap the ultra-efficient firing power design will compensate for those small variations. Should you decide to re-gap your Iridium Power plug, use extreme caution as improper gapping may damage or destroy the Iridium center electrode or porcelain center. To increase the gap size: Step 1 Use needle nose pliers or spark plug gapping tool to bend the ground strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. To decrease the gap size: Step 1 Use the same method as above, however bend the ground strap down to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN. Step 2 Re-check the gap with a calibrated gapping tool. WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.

04-03-2011, 10:52 PM
I was a Oriellys the other day and it said that my bike 2010 XB12Ss called for DCPR8EIX I know that they are the same plug just different heat rating, but do some call for the 9 and others the 8. I think the difference between the plugs is the gap. the DCPR9EIX that I got had a bigger gap than what the DCPR8EIX called for.

the difference is the heat range of the plug.

i suggest sticking with the 8. many people on here say colder is better but have yet to convince me. they are all shade tree opinions in my mind. with these bikes being so prone to fouling plugs i suggest running the 8. i have not heard of someone burning up an engine on here.

08-19-2013, 09:23 PM
What's the thread on our spark plugs? I goofed up the hole on my rear cylinder and need to clean it up with a chase I guess... :-(

04-20-2014, 07:24 PM
I know this is an old thread but just to say that I've been happy with my Denso Iridium spark plugs. I'm sure they add a bit more throttle response when I give my ride a hand full overtaking.

I think my plugs are Denso Iridium Power IU24