Iridium plugs in your Airhead?

I use Iridium plugs in my 72 Bonneville and also my 70 BSA Royal Star. With non-resister caps. The Bonnie has a Boyer, the BSA, points. For both bikes the recommended plugs are Champion N3 and N4's respectively. I too was skeptical about any performance enhancements, but was told to give it a try by a Brit bike guru. Sure enough, both bikes have seen an improvement in starting, idle and cleaner running with less fouling. They have been problem free. For me, it's worth the few extra bucks.

I tried iridium plugs in my Norton Commando race bike. On the dyno they showed about 1 horsepower improvement throughout the range.
However.. my drag racing guru friend reckons that if you get a gain from something like different plugs, there's a fair chance that your ignition system is the real problem. You might have a coil on the way out or other HT problem.

If you do some research on the web on Iridium Spark Plugs you'll find a pretty consistent 1 or 2 hp gain in most applications. My view of why that is happening is that using them has the same effect as advancing the timing slightly, with no knock conditions.

They do work and are worth a try. Lots of nay sayers but go ahead and try them, you'll be pleasantly surprised.

I have heard the same stories with all sorts of new plug designs. Remember tons of people reporting all kinds of advantages running Autolite plugs in oilheads? It just wasn't so. Still isn't!

Tracking one hp gains is more complicted than swapping plugs for another run. Oil temps and engine temps need to be duplicated not to mention tire temps and traction and that's just the tip of the iceberg. All that takes time and equipment that most for one reason or another don't have. It's hard enough on an engine dyno, let alone wheel dyno's.

How many airhead riders are going to notice an extra 1-2 hp from super-wizbang sparkplugs when they seldom see full throttle or more than 5000rpm on their tachometer?

Only if you are wearing Levi's and you Armoralled your seat.

Sometimes new plugs even if not the correct heat range will run better for a while than old crusty plugs.

So would Iridum plugs stay clearer longer, if used as the bottom plugs on my dual plugged engines, both do which tend to foul the bottom plugs?

I ran the Autolite plugs in my R1100r and they did work better with that engine than the stock plug. It got rid of the surging that the R1100 series was noted for. There are many posts with information on the benefits of this plug in those engines. It never was about hp gains etc, just drive ability issues. I'm not an engineer so I can't explain why or how, but they did affect ( to the better ) the running of the R1100 engine.

Yeah, I don't know. I've had/have two R1100S with well over 150k combined on them. I've run about every spark plug that will fit in the hole. Only time they get replaced is when the electrode is gone. And trust me, I've run them to the size of pencil lead. What makes a huge difference on those bikes is taking the time to really tune and synch the throttle bodies. I have never had a surging issue on a stock R1100S which was notorious for surging. I've also tuned it out of RTs and 1150GS by the same methods. None of the 1100/1150's should surge stock. Surging in modern computer controlled bikes is caused by the bike going from rich to lean as the computer tries to maintain a certain fuel map while looking at a lot of variables.

As for longevity in spark plugs with the FI bikes, the BMW plugs seem to last the longest. I think I just have NGK's in the airhead, but have used champion and autolite, and really, they all last a really long time, carbon and oil fouling aside. We are talking about bikes that are 30 or so years old. They just weren't weren't made to run on today's gas all the time. If you want to see a real improvement right away, go invest in some pure gas, and by some champions.

not me .. R80 G/S gets run hard all the time ... err most of the time
have not had a chance to pickup a new set of plugs yet. but for $15 what the heck, it's worth a try.

drag racing at Zombie Apocalypse Training Camp

Sorry to bring this up from the dead, but if one where wanting to use the NGK Iridium Sparkplugs (BPR6EIX) in a later model R100 with and electronic ignition, do I need to change the wires to non-resistive wires since the NGK Iridiums are only available in Resistor Based package? If one where to use the OE Spark Plug wires (5K Ohm) with these resistor spark plugs, will there be adverse affects in the ignition?

No, well yes there has to be an effect because you can't bypass ohms law and some voltage would be dropped across the resistors but it would be utterly insignificant with electronic ignition.

I wouldn't entertain it with points ignition as even if it appears to work you lost a chunk of safety margin in the spark energy. Perversely it's the points ignition that would get most benefit from fancy plugs if it could be done without excessive resistance. For me this earlier comment says it all:

Back in the early 1990's I ran Bosch platinum plugs with some special electrode that was supposed to give performance gains. Those were resistor plugs with stock plug wires. No difference could be discerned. Maybe the spark energy was less? I had no way of measuring that energy.

I typically change my airhead plugs every 10k miles (or so) and don't think iridium plugs will help. However, on my Suzuki DL650 I installed iridium plugs because they will last 30-50k miles, but I don't expect (and haven't noticed) any performance gain. Adding resistor plugs with resistor wires will (theoretically) result in less spark energy - but I doubt you'll notice. Go ahead - blow ~ $12 (?) on a pair and see how they work, no harm will be done.