spark plugs question

[Bonz]

I think NGK is one of the better plugs out there IMO, and went from the standard NGK to the NGK Iridium, just for grins, when I did my final drive swap two weekends ago.

I want to say it "tightened" up the idle a bit, but I also snugged down all my airbox-carb, carb-intake boots at the same time and all of them needed it, so my results are probably more due to that than anything.

I'll do a plug check in another couple hundred miles (about 250 miles so far)and see how they look compared to the perfectly fine NGK standard plugs I now have in the tool box.

With that said, I had noticeably better throttle response when I went to the NGK Iridium plugs in my 2003 Suzuki V Strom 1000. Can't say that I notice any change with the XS, honestly.

[cywelchjr]

Buy some iridium plugs off eBay. They're great

http://cgi.ebay.co.uk/YAMAHA-XS1100-...item53e706329e

They work great if you don't have the stock coils. If you have the stock coils you will find yourself with fouled plugs really quickly because the stock coils don't have enough juice for the bigger gap of the iridiums and you can't re-gap them cause their too brittle for that. Best to stick with something you can set to the standard gap unless you have a hotter than standard coil system. Otherwise, if you have gone with ANY of the aftermarket coil systems, then the iridiums are reportedly (with you among those reporting) a great upgrade, but seriously a mistake for someone with stock coils.

[SFerinTEXAS]

Them I must be mistaken to be so happy with at least 10K miles on my SF with stock coils and iridiums. I personally don't believe iridiums can fowl.I did considerable research on Iridium plugs and constantly found statements such as this

The spark plugs potential difference is more concentrated at the tiny Iridium tip and hence less 'spark jump' voltage is required - this can be as much as 5,000 volts less than with standard plug types. Ignition is improved and less strain is placed on the ignition system. Benefits of improved ignition/combustion include better fuel economy, increased power/acceleration and especially better throttle response.

All of which I have observed.

REF http://www.spark-plugs.co.uk/pages/t...park_plugs.htm

[b.walker5]

All spark plugs can foul, even those Mercury perma-gap things that used to be popular in two smoke outboards.

Check out whats coming...

http://www.bbc.co.uk/news/science-environment-13160950

[SFerinTEXAS]

All spark plugs can foul

That part of my post was opinion I admit. Expected a challenge and fairly so. The main point I was making is that I am convinced iridiums with stock coils is an upgrade. They wont cure a a badly tuned bike, but will improve a well tuned stock bike.

[cywelchjr]

I'd heard that there were problems with iridiums with stock coils, but if there are not, then I'm clad to be wrong, and I'll stop giving what appears to be incorrect advice. For that matter, if they do help with the stock coils, I may give them a try since every little bit helps in any case.

[petejw]

im running mikes xs black coils and didnt like
the iridium plugs, they seemed to run hotter
and not as well as the stock ngk plugs.

tho i did do the side gapping as bikerphil posted
on the stock plugs and also had them indexed,
am real happy with that setup.

[James England]

I must say, I've never used the iridium plugs with anything other than 3 ohm Dyna coils.

Don't the later XS1100's run on 3 ohm coils anyway? They did away with the ballast resistor and 1.5 ohm coils after only a couple of years, didn't they?

I did read that iridium plugs can be re-gapped. Isn't it only the central electrode which is iridium? The part of the plug which the spark jumps to is just normal plug metal and can be bent.... I think..... I just plonked my plugs in as they came out of the box.

[bikerphil]

Don't the later XS1100's run on 3 ohm coils anyway? They did away with the ballast resistor and 1.5 ohm coils after only a couple of years, didn't they?

James, the 81 is the first year (US models) with no ballast and 3Ω coils.

Pete, yep I like the side gap plugs too, combined with the relay mod, my bikes definitely run noticeably better.

[natemoen]

I'll stop giving what appears to be incorrect advice.

Yeah like that will every happen Cy!

[Bonz]

I fine-tuned the gap on the NGK iridium plugs when I put them in, and no problems with breaking the center electrode.

I did go into the gapping of the iridiums with the knowledge that some folks feel they are more fragile, and just took reasonable care not to put crazy force into the operation. Set mine at .027", more or less in the middle of the recommended gap range.

Part of my decision to go with iridium in general is the lower voltage needed to initiate the spark jump, and figured that would be coil friendly to my stock coils.

As well, for what it's worth, I've heard all iridium plugs aren't the same. Kind of like "synthetic blend" motor oil. The iridium content in different makes of plugs varies, and from what I understand, the NGK plugs are on the higher side of iridium content, so that helped my choice. Someone can add to that or correct me if I'm incorrect.

In 250 miles of riding, I really can't tell a difference with the iridium plugs in the XS. My XS is tuned very well, so in that sense I can understand why I might not feel any seat of the pants difference.

I said earlier, on my V Strom 1000 I put the Iridium plugs in when doing a valve adjustment, throttle body sync (fuel injected), and even with a freshly tuned and dialed in motor, I did notice a much better throttle response that there was no denying on that bike.

[petejw]

Pete, yep I like the side gap plugs too, combined with the relay mod, my bikes definitely run noticeably better.

phil, ive done the relay mod as well.