Spark Plugs

[p_s]

One interesting thing about the data is that the NGK Iridium plugs have the most consistent set of runs. I'm not sure we can infer anything from this as I mentioned before, we dont know what the test conditions are. I guess I might be disappointed, but I am expecting an improved drivability for my stock 750 from a set of NGK Iridiums.

Sure. I don't remember the details. It was a new car with a new ignition system, warmed up, with new plugs. But there are many reasons besides hp & torque that could justify spending more money on plugs. If it made my bike start more easily when it's 15 and I *lost* a horse or two I'd be happy to put down my $32. Let us know if you find a difference.

[crazedfooter]

not that i run the expensive plugs but from the info above threre is a 2 or 3 horsepower difference with some of the plugs, 10 bucks per horse seems pretty reasonable to me, i know people have spent more.

my 2 cents

nick

[Tarbash 27]

I got the iridiums for my gs750 (br8eix). I really did not notice a difference in power just from the plugs because at the same time I changed to dyna s and dyna coils with wires. But I know one thing, these plugswill probbaly last a few years before they need replacing. I also got them through my work for cheap.

Alot of these cars now require platinum plugs. I work at an autoparts store and sell the ngk laser platinums to people everyday for about $15 a plug. But thats the only thing to really replace these days with the coil on plug distributerless ignition systems. So you spend about $60 for a "tune up". Now you take a 35 year old car, cap, rotor, wires, plugs, points, etc. About $60 there too. Oh well.

[Clone]

I really doubt that you will get power gains, but one thing that was demonstrated to me by the NGK rep was that the fine electrode plugs like the G-Power or Iridium plugs have a more focused spark than a standard electrode plug. He also touted them as producing a hotter spark with lower power input.

[Mysuzyq]

Have not tried the Iridiums, but FWIW, I hear they are a lot less prone to fouling than conventional plugs, esp. the ND Iridiums, which feature the smallest electrode tips around.
I always thought the hp claims with Splitfires, etc. were BS, but an independently verified 2-3 hp gain (and 5 ft/lbs of torque!) with the Iridiums seems pretty decent and hassle-free, compared to the time/effort/money needed for typical mods to the intake/exhaust (which, improperly done, will negatively effect performance).
Tony.

[tkent02]

If you had a modern computerized fuel injected engine, which constantly monitors and adjusts fuel flow and ignition timing to match every little change in fuel quality, atmospheric temperature and pressure, engine temperature, etc. you might see a little bit of this 1% or 2% power gain. Not that you could feel a gain that small but it might be there. On these old, carburetor fueled engines with their constant advance ignitions, most of which are not tuned very well anyway, it is snake oil, at best.

[focus frenzy]

If you had a modern computerized fuel injected engine, which constantly monitors and adjusts fuel flow and ignition timing to match every little change in fuel quality, atmospheric temperature and pressure, engine temperature, etc. you might see a little bit of this 1% or 2% power gain. Not that you could feel a gain that small but it might be there. On these old, carburetor fueled engines with their constant advance ignitions, most of which are not tuned very well anyway, it is snake oil, at best.

most all modern cars have very strong ignition systems and have little to no trouble firing a spark across a worn plug. in fact they have a excess of power due to (in America at least) having to meet the Gov mandated emissions standards. modern cars have to be able to pass a emissions test without requiring replacement of parts for 100,000 miles, so platinum plugs have become pretty much standard equipment.

our bikes have a relatively weak system and stock don't have a real hot spark when cranking over so anything that can help it is a benefit.

when I put in the iridiums I did not notice any real improvement in power but could tell a slight difference in low end torque and mainly a pretty good improvement in starting.

both my bikes now have hotter ignitions, Bob (1000G) has Dyna coils with accel wires with the ignition bypass mod, and Rosie (1100e) has accel coils and wires. so other than much longer life there is little difference.

[jbs80106]

They don't seem to carry these for motorcycles...

Seems to make technical sense to me. Don't know how they compare to irdium plugs which seem to be the way to go for my 650.

http://www.haloplugusa.com/

[Clone]

There are a lot of special design plugs out there, NGK has some two electrode plugs that go into quads, and they don't shroud the positive electrode. Those halo plugs seem to shroud the positive electrode a lot.


I am interested in knowing the temperature of the spark between a standard plug and a fine positive electrode (G-power or Iridium). The difference would be interesting to see in conjunction with the input power.

[Greg O.]

The only time I have trouble with starting is when it gets below about 45 degrees. That is when I occasionally foul out a spark plug or two, but I think that is from using the choke, as these engines are very cold blooded. I have a spark plug cleaner in my garage, and pull them out and clean them. I have had times when one would miss fire til the engine warms up, then starts hitting on all four. I only have problems late in the fall or early spring when the temps are really cool, almost to cool to ride. Otherwise the stock NGKs work great.

Greg O