Was going to change the plugs on my 99' model. Was thinking about using NGK's Iridium plugs. Have them in my old GPZ1100 and they make a difference (mainly to starting). Just wondering if they are worth it on a more modern bike?

 

Bump my old thread as I'm considering it again.

 

I think it was Flogger fitted them, Coopz - said he was impressed with the difference it made - helluva price difference here, though.........[8D]

 

I have them in my 1991 FL bike.

The combination of irridium plugs , a K&N filter and a quick tune up made a big difference.

Bike seems to pick up better from low revs and the tank range has become better.

It also heads for the redline on the tachometer very quickly now if you pin the throttle.

The last tank of fuel was at a more touring pace rather than fun & frisky - got 215 miles to reserve.

With gas at the current price of £5.00 a gallon ( YES - nearly $10 a gallon ) - the price of the plugs was
irrelevant.

 

I believe that a plug can either ignite or not and as long as a stock plug ignites it works just as well, i.e. delivers the same performance. The motive for Iridium plus are perhaps higher on very modern engines which runs so clean that the plugs will rather burn down than ever getting fouled. Iridium plugs will last very long in a clean burning engine, as all modern vehicles are, except perhaps Royal Enfield and similar.

I'm using standard plugs on my Suzuki 2003 and replace them about every 25 000 km, they still look almost like new after 25 000 km's and would probably make the double or more. On my Blackbird, I'm using Iridium plugs and have no plans to replace the more often than 60 000 km or so.

I'm also using Iridium plugs on my car; this is to have the possibility to really forget changes. I replaced the first set after 160 000 km's and they looked like new. I've heard that e.g. modern taxi cars often runs 200 000 km on the plugs before bothering of changing them, and this would not be done if the cab owner looses money by not changing plugs more often.

Bottom line, if the engine is in good condition, then one could use Iridium plugs for convenience and change very seldom. If the engine is worn and fouls the plugs now and then, it is much cheaper to use stock plugs.

Curiosa -one can not adjust the gap on Iridium plugs as on stock plugs. It is recommended that one never adjust the gap on Iridium plugs since this willdamage the protective surface.

 

You don't need to adjust the gap - the plugs can be bought with the correct gap.

the end of the plug part number " -9" is the gap size -9 = 0.9mm


http://www.ngksparkplugs.com/docs/te...tnumberkey.pdf