As far as checking the gap on my new plugs, it is WAYYYYYYY smaller than the OEM ever was, I'm sure. These are not single electrode plugs like OEM, they are split electrode. Is there any way to check the gap on these? Are they supposed to have such a small gap?

Why split electrode? I just wanted to try it. It was recommended to me on this thread a few years back. Supposed to promote better combustion. Third post.

http://www.bikeland.org/board/viewthread.php?TID=54941&FID=27

* Last updated by: Rook on 9/11/2015 @ 1:23 PM *

A Barfland thread? No thank you.

Your well advised to put in new versions of what you pulled out.

I'm sure not keen on tossing out 4 new spark plugs. What could be the worse thing that would happen?

Im torn on the spark plug discussions. Rook If I had those already I would most definitely be trying them. Just because.

To often in thousands of cases the story always comes back to life lesson of
"Never Ever Ever Deviate From Manufactures Specifications".

With that being said you would think I would run stock plugs in my turbo bikes but I don't. I'm told by the turbo gods to run the cheapy plugs with the larger electrode for better heat dissipation. So I do. Honestly I see no difference and I have switched back a forth a hundred times.

Sorry I could not be of much help.

What could be the worse thing that would happen?

The bike runs better but the plug fouls quickly ? Important to note, those plugs were the stock recommendation plug for the ZX12,,,, What reason Kawi had for going away from them is the Question. Maybe just to damn pricey

Rook If I had those already I would most definitely be trying them.

The bike runs better but the plug fouls quickly ?

Sorry I could not be of much help.

Now about the gap, I'm going to assume spark plug gaps are set at the spark plug factory to make the plug work optimally. It is not necessary to change the gap according to the vehicle it is put in, is it? You just check the gap on a new plug to be sure the electrode was not bent by accident, right?

I suppose its worth running them Rook. Everything I've read is the CR9s are the plugs to run in this beastie.

Turns out you can measure the gap on the split electrode plugs. You have to slide the gauge around the side of the center electrode instead of from above. It was about .78 mm. If my research from years back is correct, the gap sould be .8-.9 mm on a standard plug so I did not mess with the gap on these. Besides, it looked possible that the porceline would chip if I pried against it while opening the gap a touch. I'm assuming NGK got it right. The gap will widen as the plug wears.

I used this to blow out the wells while sucking at the top of the well with a vacuum. The tip was melted shut with a heat gun and then I cut an edge off to open a small hole for added air pressure. The other end was heated up to fit over the barbed fitting. Hagrid, that Legris hose was too nice to do this to. I have that saved among the other gems in my tool box to be used for something much more worthy than blowing out spark plug wells. I still like the gun with steel tube as inconvenient as it is to fit under the air box, it allows for one hand use while you hold the vacuum with the other hand. The plastic hose tends to want to blow itself out of the well unless you use one hand to hold it in. You might get one hand operation with a plastic hose if you cut it short enough. This one was way too long.

* Last updated by: Rook on 9/13/2015 @ 3:36 PM *

I'm glad to have new plugs but no discernable difference from the 44,000 milers.

"I'm glad to have new plugs but no discernable difference from the 44,000 milers"

Changed the plugs on my car at 100,000, no difference, same thing with my truck,

I emailed NGK Friday, and asked them why a motorcycle would need an Iridium plug
replaced at 7500 miles, when many a high performance car engines say 100,000 ?

I will let you know if they reply back ...

My mech swapped the plugs...

Specs from NGK:

http://www.ngk.com/product.aspx?zpid=9687

To this:

http://www.ngk.com/product.aspx?zpid=9688

Is this needed?

http://www.ngk.com/product.aspx?zpid=9687

Plugs look dry, no oil up the threads... nice tight motor.

I wonder if the main reason Kaw suggests changing plugs so soon is so you don't see all the crap that will build up if you let them go a lot longer?

static369, I see a gradual increase in carbon from the bottom plug to the top in your pic. The top 3 are close but the uppermost is a little dirtier than the rest and second from bottom is definitely cleaner than the top. Are these plugs arranged from bottom, cyl #1, 2, 3, 4 with cyl#1 being cleanest? If so, that's the same deposit pattern mine had. ALSO, how many miles were on these plugs?

From NGK :

Hello,

The reason that the motorcycles are required to change the plugs more often is that the bikes run at higher RPMs and puts more load on to the plug. If you track your bike, or do any street racing, you will need to change the plugs out sooner than that.

Thank You,
Lela Martin
NGK Spark Plugs, (USA) Inc. || http://www.ngksparkplugs.com/
46929 Magellan Drive || Wixom, MI 48393
Direct: (248)926-6313
Fax: (248)926-6938
E Mail: lmartin@ngksparkplugs.com

Rook, plugs are like 8000 KM old. Not arranged in any order. The bottom one was dropped therefore the tip is slightly bent... Are the ones currently installed in my bike a upgrade over the stocks?

Question is why did they use the non OE plugs? Did you ask the why, what was their answer?

Interesting the 'rating' on their own website.Certainly doesn't appear these plugs are 'superior' in very much.Surprising really.

Are the ones currently installed in my bike a upgrade over the stocks?

I couldn't answer that, static. All I know is that if the OEM ones can go over 44 thousand miles without a problem, there's nothing that's going to be a lot better unless it enhances performance and that will only be hotter or cooler for turbo applications. I really doubt any noticeable performance can be noted through spark plugs on a NA bike. A spark plug's a spark plug. The only issue is how long you dare to leave it in before it fouls or god forbid, the electrode breaks off. JMHO based on my 1 little endurance test of OEM spark plugs. I expect these new ones will foul if I leave them in half as long but they don't do anything for performance. Any high quality spark plug that fits the hole and has a single electrode like OEM is going to as good as the next. But I'm no spark lug expert.

by looking again it seems the only difference is the terminal. the OE plug is a threaded stud. the one they put in has a removable nut over the threaded stud so they had to remove the removable nut to use it in your bike.

I'm still thinking 7500 is too early for a street rider, NGK says its because of
the "high RPM" of a motorcycle engine, well even a Honda Car, the S2000,
revs at 9000 RPM'S and their plugs don't say to be changed until 100,000 ???

I've got about 40,000 miles on my Connie and haven't even looked at the plugs yet. It runs better than new.
It's to get morons in the shop. If you took your bike to the dealer and told them to perform a full 7,500 mile service per the manual, they would change the oil, and lie about the rest.
The same with most valve adjustments and carb syncs.

I'm still thinking 7500 is too early for a street rider

It's to get morons in the shop. If you took your bike to the dealer and told them to perform a full 7,500 mile service per the manual, they would change the oil, and lie about the rest.
The same with most valve adjustments and carb syncs.

couldn't agree more...but moron might be a bit too string of a word. "naïve," maybe. I'd check at 7500 but I know it isn't necessary to change. I think 10k miles is prolly a good benchmark though they ought to go longer. Why push it. But yeah, avoid the shop like the plague and if they say they're doing something, tell em you want to observe or see photo evidence they actually did it.

Gap - every spark blows off pieces at the side and center electrodes = As the gap widens.
Electrolysis - heat plus electricity causes the threads to lockup = With heat the magnetic field combines chemistry.
Performance - it's all about gap speed and the time it takes to fire = The sooner the flame front, the sooner the burn begins.

And at those rpm speeds, those split seconds, the cleaner surface the spark can pass over, the sharper cut at the center and side electrodes and that shortest path to jump = It starts sooner, is more crisp, burns more efficiently.

I know it's quite an old thread but it may help anyone who's searching for this kind of information either for the ZX14 / ZZR1400, Concours14 / GTR1400 or even any other bike.
I have a 2006 Gen1 ZZR1400. I bought it in 2015 with about 80k km/ 50k miles. Spark plugs had been changed at around
75k km / 47k miles according to previous owner. Currently I'm in the process of adjusting valve clearances. It's the 1st time since ownership I'm doing it: 2 exhaust valves slightly out of spec - 0,18 and 0,20mm (spec=0,22-0,27)and 1 intake valve also slightly out of spec - 0,12mm (spec=0,15-0,20). I'm also in the process of fixing an issue with fueling/ stalling/ misfiring/ poor fuel economy (I think it's dirty / clogged fuel injectors, but I haven't yet reached a conclusion), which is not related to spark plugs (I put new ones and didn't fix the problem). Bike now has 185k km/ 115k miles and spark plugs are still the ones replaced at around 75k km / 47k miles. I'm going to change them just because I'm at it and the bike it all stripped off. I don't race the bike and use it mainly for touring purposes and it's ridden quite sensibly. I'd say 99% ot the time below 4500 RPM. Bottom line: 7,5K miles / 12k km can be stretched if ridden like I do it (mine were NGK CR9EIA-9, lasted for at least 110k km / 68k miles and will be replaced by the same).

* Last updated by: zzriderpt on 6/9/2024 @ 3:49 PM *

Book calls for every 7,500 miles. Did you check the air cleaner? Those are changed every 12,000 miles. Might want to take a compression test with that high a mileage. Maybe it will point to the poor running.

See the valve clearance values of min/max? So max gap is the aim. Quieter, less ticking, more grunt. By using a wider gap, it prolongs the power stroke before you open the valve. Tight clearance on that end shortens the power stroke.

So the theory of making HP is not more air, but how fast you can bring the action back and start all over again. Being a normally aspirated engine closes at 14.7 psi or atmosphere every time the intake valves are closed.

You'd need a super charger or a turbo to have more air pumped into a NA engine.

Plug threads on the used spark plugs have oil running up the threads? Plus at the nose of the porcelain show a dark tan?

I went about 11k miles (mixed riding) on a set of plugs and was blown away by how much better it ran after changing them. And I don't think I would've even thought the bike was running "bad"... but it was noticeable difference. So yes you can run them longer than 7500 miles but I wouldn't go past double that even riding around never exceeding 4k.