Took 8 replies for this to come up? You guys are slipping!

 

I have always had good results running ordinary Autolites.

If it is on your Evo, change the wires if they are still the original on the basis of age / preventative measure.

 

Joe, running a standard plug is the least of your problems. You make your own calamities. Learn to prioritize.

 

I have 111k miles on my Fatboy and run the NGK DCPR7E standard plugs in my bike with no issues at all.

 

I thought this video was interesting. Cycle solutions does a before and after dyno after adding NGK irridium plugs. Shows a 2 hp/ 2 to increase

 

I plan to do a complete tune up if possible in spring so this thread is quite related.

Sorry to disagree but the bike was a calamity when I got it. I didn't create the headaches that I'm having with it. This is an example why I have my nick,cause half of the "calamites" are not of my doing. 1/4 is indirectly my fault. The last 1/4 is mine to own up to. Anyhow I prefer this subject be in another thread in another time.

I have prioritize the list of needed repair but come spring First thing to fix is the throttle cable/carb. Next is the oil leak. Last is replacing wires,fluids and spark plugs. Last is replace the exhaust pipe and that may have to be done.

 

Standard.

 

One of the reasons I do all my own work is cause I don't want somebody "freeballin" a ratchet when there is a torque spec for the plugs. I am sure the tech has the "feel" but that is what a heli-coil is for.

 

I answered "Standard" but it really depends on what you are after. Iridium is the most dense of the materials used for Spark Plug Electrodes and therefore it will last the longest. The question is really how long do you want to go between Spark Plug changes? 100,000 miles? Really? Platinum will continue to oxidize (burn) hydrocarbons at temperatures as low as 600*F (Typical Combustion Chamber temperatures exceed 2,000*F) and thus is best if you are running rich mixtures for a high percentage of the time. Rich mixtures will increase HP up to a point which is what is in a lot of the "Magic" that various "Tuners" do. If this is what you are (or your Tuner is) doing, the risk of fouling a Spark Plugs is elevated and running Platinum Spark Plugs has real value. Then again both the center and the side Electrode need to be made of Platinum to have the best effect. Most Spark Plugs advertised as being Platinum only have the center Electrode made of Platinum or worse yet only place a platinum "button" on one or both Electrodes, which does rather little. Platinum is more dense than steel but it is not as dense as Iridium. So if the reason you are using Platinum Spark Plugs is to gain extended life . . . use Iridium, it'll last a bit longer than Platinum. Splitfire Spark Plugs are worse than Standard Plugs because the Split Side Electrode does nothing to improve the Spark and in fact tends to shield the Mixture from the Spark, thus increasing the percentage of misfires. Lastly, replacing any set of used Spark Plugs with a new set of Spark Plugs will generate a slight increase in HP because a Spark will jump more easily from a sharp edged surface than a rounded one. New Spark Plug Electrodes have sharp edges and as a Spark Plug wears these sharp edges become rounded. This increases the misfire rate ever so slightly. As a result, replacing used Spark Plugs of any design, with new Spark Plugs of any design will show a minor increase in HP. When I was racing, we used Standard Spark Plugs and replaced them after every race.

 

For many years, going back into my 20's, I've heard some Indy mechanics say use Autolites.

I've used them since then and they work well for me...and they're pretty cheap.