SuzukiSavage.com - Iridium Spark Plugs Worse for Bike?

d3adrock

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Iridium Spark Plugs Worse for Bike?
11/06/20 at 14:48:11

Hi Everyone, I was out riding and getting ready to pull in to park, suddenly the bike died. No matter what I did I couldn't start it. I could hear the starter working but it wouldn't turn over. I gave up and had it towed to the mechanic. They took a look at it and said the spark plug had fowled as a result of the main jet being too rich. I had a hard time believing that because it seemed to run fine for me. In any case they replaced the spark plug with a standard one, instead of the iridium ngk that was in there. When I asked why not another iridium, the man said that sometimes iridium spark plugs are worse for a bike if it's not designed to use one (news to me) and it was better to put a standard plug in it.

Has anyone here ever heard of such a thing as iridium being worse? I thought iridium was always better/more durable?

What do y'all think was there any truth in what he said?

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Gary_in_NJ

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Re: Iridium Spark Plugs Worse for Bike?
Reply #1 - 11/06/20 at 15:54:05

First off, dealers LOVE to blame any failures on any change that an owner made. If the dealer believes that the main jet was too rich, they they provide any evidence to that? You can always remind them that 80% or more of your riding happens on the needle (unless you actually ride at 75% throttle or higher all of the time). Anyway...

For a low voltage ignition system such as the Savage’s, expensive spark plugs are a waste of money. A standard NGK in the standard heat range is the way to go. I don’t know if an iridium plug is more likely to fail in a low voltage ignition system, but I also don’t know if you had the correct plug installed to begin with.

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Matchless G11 Senior Member Offline SuzukiSavage.com Rocks! Posts: 451 Newfoundland NJ	Re: Iridium Spark Plugs Worse for Bike? Reply #2 - 11/06/20 at 16:35:18 What was the old plug heat range? We would call plugs for racing "refrigerator plugs" (cold)
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Dave

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Re: Iridium Spark Plugs Worse for Bike?
Reply #3 - 11/07/20 at 02:33:52

I have been using an Iridium plug in my Savage for the last 12,000 miles and it seems to be fine. I don't use it for any performance gain - I use it because those plugs last 100,000 miles in my car!

I have never fouled a plug in my Savage.....or any other 4 stroke engine that I own. If you have fouled a plug - maybe the dealer is correct and you are running too rich.

What jets and needle changes have you made.

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d3adrock Full Member Offline Posts: 111	Re: Iridium Spark Plugs Worse for Bike? Reply #4 - 11/07/20 at 08:17:19 It's got a 20 starter jet, a 195 main, and a 159 Q2 needle jet with the needle set to the third position.
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Dave

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Re: Iridium Spark Plugs Worse for Bike?
Reply #5 - 11/07/20 at 09:45:08

d3adrock wrote on 11/07/20 at 08:17:19:

It's got a 20 starter jet, a 195 main, and a 159 Q2 needle jet with the needle set to the third position.

Those jet numbers don't mean anything to me......what kind of jets are they?

Mikuni jets should be #150 Main, #52 Pilot......and I am not sure what you tell you about a needle with multiple settings for a clip. Maybe early bikes or aftermarket needles had clips.....later ones only have one slot for the clip and you have to modify the white spacer or use washers in place of the spacer.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28890 L.A. California Gender:	Re: Iridium Spark Plugs Worse for Bike? Reply #6 - 11/07/20 at 09:46:48 sounds like he has a VM dave. at least, not stock.
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d3adrock Full Member Offline Posts: 111	Re: Iridium Spark Plugs Worse for Bike? Reply #7 - 11/07/20 at 10:18:48 I forgot to mention I have a vm36
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Ruttly

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Re: Iridium Spark Plugs Worse for Bike?
Reply #8 - 11/08/20 at 14:10:13

If properly jetted a standard plug should last a good long time. Me I only run NGK or Denso plugs in all my jap bikes, BSA and the Harley too ! For awhile Denso was making Harley plugs. Only change the plug when it’s getting a valve adjustment or if it gets fouled during jetting. A lot of those fancy plugs don’t have a heat range like recommended by bikes manufacturer. Platinum and Iridium plugs do last what seems to be forever and work just fine. My favorite plug is the Denso with the Hot U electrode. Have never had one fail/foul in 40 years.

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d3adrock Full Member Offline Posts: 111	Re: Iridium Spark Plugs Worse for Bike? Reply #9 - 11/08/20 at 15:50:28 So would you reccomend the standard ngk plugs over the iridium ones? Or would you say iridiums are better?
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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5113 Manteca , CA Gender:	Re: Iridium Spark Plugs Worse for Bike? Reply #10 - 11/08/20 at 20:27:05 For a Savage a NGK or Denso stock or modded is best , you won’t gain anything by using iridium or platinum but you will have less money to spend on other performance parts like piston,carb,exhaust & porting. I’m pretty sure all of the big 4 jap manufacturers all recommend NGK or Denso.
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d3adrock Full Member Offline Posts: 111	Re: Iridium Spark Plugs Worse for Bike? Reply #11 - 11/08/20 at 20:56:15 Do you think it's possible that removing the front turn signals somehow caused the spark to malfunction? The guys at the mechanics said no, but I'm not sure.
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Gary_in_NJ Serious Thumper Offline LS650 Cafe Racer Posts: 2633 Amongst the Twisty Roads	Re: Iridium Spark Plugs Worse for Bike? Reply #12 - 11/09/20 at 06:25:31 d3adrock wrote on 11/08/20 at 20:56:15: Do you think it's possible that removing the front turn signals somehow caused the spark to malfunction? The guys at the mechanics said no, but I'm not sure. No.
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d3adrock Full Member Offline Posts: 111	Re: Iridium Spark Plugs Worse for Bike? Reply #13 - 11/09/20 at 06:27:20 That makes me feel a bit better. I blamed myself for it because of those darned signals.
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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5113 Manteca , CA Gender:	Re: Iridium Spark Plugs Worse for Bike? Reply #14 - 11/09/20 at 10:08:50 I highly doubt it.
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