Spark Plug Questions

Wayne Broderick /

There is an earlier post/thread saying that NGK plugs will damage a Tomos Targa. Is there any truth to this? Is it something I should be thinking of?

Also, someone said in that same post that splitfire plugs would be bad for a ped-- (I had never even thought they made splitfire in 'ped size...)

anything for a performance boost.... !

can someone please post the equivalent of a "moped sparkplug F.A.Q.??"

Thanks a million!!!!

Re: Spark Plug Questions

the best spark plugs for mopeds, hands down, seems to be bosch platinum. most "standard" mopeds (puch, minarelli, garelli) seem to use a 4214 bosch platinum. this is equivalent to a champion L86C. you can cross-reference it at most auto parts store.

also, a link found in our "resources" section is for spark plug cross reference by major brands:

<A HREF=""></A>;

Re: Spark Plug Questions

Chris Robertson /

I highly doubt that changing your brand of spark plug will give you any noticeable performance increase.


Re: Take those plugs and shove em !

Wayne Broderick /

Chris, you should see the earlier thread I refer to. Pretty much says splitfire will damage your piston and that NGK can kill your bike.

Read this thread on this same forum. I would say that haviing a running bike is quite a "performance Increase" from a bike that won't run!!

or, do you disagree that a running moped will outperform a non running ped?

Here's the thread I refer to in the original post.

Moped Army:

Take those plugs and shove em !


Re: Take those plugs and shove em !

Chris Robertson /

Hi Wayne:

I was responding to a comment you made in your initial post in this thread:

"<font color="blue">anything for a performance boost.... !</font>"

Spark plug <i>brands</i> are like toilet paper brands, motor oil brands, plastic wrap brands, light bulb brands, garbage bag brands, etc. The only thing that makes them different from one another is advertising and marketing (many people will disagree with me on this of course).

Assuming you use the correct spark plug (as recommended by your moped's manufacturer), you will not see a performance increase/decrease by changing <i>brands</i>. You might see a difference in how long the plug lasts, but that's about it.

The only way you can damage your piston with a spark plug is if you get one that is too long, or you run a heat range that is <b>way</b> off manufacturer's spec.

FYI: <a href="">Consult this page</a> for information on how to read NGK spark plug codes.



Re: Take those plugs and shove em !

maybe it's all psychological ... but we all seem to run better w/ bosch platinum. everyone here swears by them.

There is a reason Ree could only find NGK's

And the reason is that NGKs have become widely accepted by spark plug buyers as very good plugs at a good price.

So... No... NGK's are not going to "kill" your motor.

And... No ... they are not "bad" plugs.

I use them almost exclusively.

But my bikes are all made in Japan too.

Which is where NGK's are made.

And I tend to agree with the idea that.. "using Jap plugs in Jap bikes" and "use Euro plugs in Euro bikes" is probably an OK plan.

But I also agree with the idea that if you have real bad luck with NGK plugs say.. more than 1 plug per year).. that your jetting is off (or there is some other problem).

Re: There is a reason Ree could only find NGK's

Reeperette /

Everyone's pretty much said the rest, so I will just add a couple bits.

Mopeds, whatever country they are made, are made with local parts in mind.

And what causes some of the difficulty, my best guess - is the difference in heat range even on plugs that are identical on paper.

NGK kick ass in Yamaha, Honda, etc.

Bosch kick ass in Puch, Tomos, etc.

Apparently Japanese and European heat ranges don't seem to match up exactly, and if you are running a "Tricksy Mix", trying to squeeze a hair more performance....yeah, yer likely to run into problems.

But thing is, mopeds, generally, seem to be as individual as their owners...I've seen matched pairs have different "preferences" as far as mix, plugs, etc.

For whatever reason, mix, carb adjustment..whatever it may be, not once have I gotten any decent performance from an NGK Plug in a Tomos, but remember, alla my 'peds are individually tuned, by me - YOUR milage may vary, as it were, although I've seen enough Tomos owners cussing over the same problem in my time.

My current problem was a combination of dying plug, and dying coil, and I've not seen that happen before, not both at imma check for an underlying problem that might have caused that.

As fer splitfire, I've had a couple of folks I knew on the east coast bitch to me about knocking a hole in their piston with them, apparently the spark hits hard and concentrated right on the top of the piston, and with consistent hard use, it more or less drilled a hole in it.

I didn't believe the guys till they brought a piston to show me, and yeah, there was a hole right through the top.

HOW that occured goes beyond my knowledge of engines, but best guess would be it runs way too hot and concentrates that in a small area, and moped pistons are much smaller than auto or cycle pistons.

Of course, they were running a thinner gasket than reccommended too, and that might have had to do with it.

General reccommendation is to use the plug the manual calls for, and if that's not possible, at least try to stay with plugs from the same continent.


Re: There is a reason Ree could only find NGK's

Go,Ree! You must be dead on right,my friend! I called Suzuki's head mechanic about this and he informed me to NEVER use anything but NGK in those `Jap Jobs'.And I know how well the BOSCH plugs do in European bikes.This guy was as convinced as I've seen of his statement and I'm sure he knows what he's talking about.But I never put it together until your last post.THANKS!

Re: There is a reason Ree could only find NGK's

I've had this problem with splitfires on an old chevy 302. Not quite the same but it does fit here. The split electrode actually seems to funnel the flame straight down onto the piston, overheating the one spot slightly, and little by little it vapourizes a hole in it. Something like a V-groove would be better. Still multiple spark paths, but directed to the side. It seems to help the "swril factor" as well.

I have found with other small engines that platinum plugs DO give a performance boost, however slight. They do allow for a stronger spark owing to their lower internal resistance, and there is a small catalytic action between the platinum and the fuel. Especially if you use an alcohol based additive. In model airplane engines a platinum glow plug is used and it's only kept running by the heat stored from the last ignition and the platinim/alcohol fuel reaction. A 0.46cu engine can hit 2.5hp!!!


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