[re-rider]

PROBLEM!
I have purchased a Bosch YR7MES and a Bosch YR7NII33S spark plugs to carry as spares, but on receiving the plugs I found the top thread was not exposed like the one fitted to my Supernova, so I attempted to remove the cap, which on most plugs usually screws off to expose the thread, but on using some force I found the plugs do not have a removable cap, and destroyed both plugs by separating the core. Has anyone else come across this problem as I haven't got a clue what the remedy is. Anyone know the equivalent plugs i.e. NGK, Champion etc. 

[tooseevee]

PROBLEM!
I have purchased a Bosch YR7MES and a Bosch YR7NII33S spark plugs to carry as spares, but on receiving the plugs I found the top thread was not exposed like the one fitted to my Supernova, so I attempted to remove the cap, which on most plugs usually screws off to expose the thread, but on using some force I found the plugs do not have a removable cap, and destroyed both plugs by separating the core. Has anyone else come across this problem as I haven't got a clue what the remedy is. Anyone know the equivalent plugs i.e. NGK, Champion etc.

           There are many cross reference charts available all over the internet. You can easily find a match in a Champion or Autolite or a lot of other good plugs.  I've never come across any of these plugs that won't unscrew in my whole life. Where are they coming from?

[Dexter]

           There are many cross reference charts available all over the internet. You can easily find a match in a Champion or Autolite or a lot of other good plugs.  I've never come across any of these plugs that won't unscrew in my whole life. Where are they coming from?

I just did a search for a cross reference to this Bosch plug and came up empty. No site that I found recognizes a Bosch YR7MES. Anyone else do better?

BTW - I have never carried a spare spark plug in my life time of riding and never needed one.

[tooseevee]

I just did a search for a cross reference to this Bosch plug and came up empty. No site that I found recognizes a Bosch YR7MES. Anyone else do better?

BTW - I have never carried a spare spark plug in my life time of riding and never needed one.

          I believe that plug (Torch YR7MES) is a Chinese made ripoff of Bosch plugs.

          OR they're made in the Chinese Bosch factory. The brand name in China is Torch.
 
          That may or may not be why they're not in the cross reference charts.

           You can't assume where ANYthing is made nowadays.

https://europe.autonews.com/article/20110920/ANE/110929997/bosch-begins-building-spark-plug-plant-in-china

         

 

[GSS]

Tooseevee, nice info on the Torch plugs being similar to the Bosch YR7MES….may help us eventually narrow down the search. Hoping that HCM will get us there first with a NGK offering. 

[Dexter]

Tooseevee, nice info on the Torch plugs being similar to the Bosch YR7MES….may help us eventually narrow down the search. Hoping that HCM will get us there first with a NGK offering.

I have searched using Torch and got no where.

[GSS]

I have searched using Torch and got no where.

+1

[tooseevee]

I have searched using Torch and got no where.

    Here's a clue:

https://www.aliexpress.com/item/32854267825.html

    You can do some more digging if you want.

     It doesn't surprise me at all that there are no (or very rare) cross-reference charts for this plug.

[glencoeman]

Why are people looking for spare spark plugs? New spark plugs for the Meteor are not even recommended till the 12,000 mile service even though the old ones would still be OK. It's early days folks, so wait a while and NGK etc will start making spark plugs suitable for the Meteor, if you really want a spare. 

[Dexter]

Why are people looking for spare spark plugs? New spark plugs for the Meteor are not even recommended till the 12,000 mile service even though the old ones would still be OK. It's early days folks, so wait a while and NGK etc will start making spark plugs suitable for the Meteor, if you really want a spare.

Other than the OP, who is looking to carry a spare plug, I think the rest of us were just looking for curiosity's sake, trying to help the OP out in his quest. It would be nice to know if there is a NGK substitute for future needs, but that doesn't appear to be the case at this point.

As for me, I typically keep spark plugs in service for at least 30,000 miles. If one went with iridium plugs, they can do 100,000 miles no problem.

[GSS]

It is our incessant quest for knowledge 

In all seriousness, while the OEM Bosch plugs are fine, the NGKs have successfully been used on this forum for settling down minor issues with the UCEs and other engines, especially after any performance modifications. It will be good to have alternatives identified in advance. Thanks.

[GSS]

Y - M12x1.25, 16 mm socket
R - With interference suppression resistor
7 - Heat range
M - see photo for dimensions
E - Nickel yttrium
S - 0.7 gap

[xpop]

so I attempted to remove the cap, which on most plugs usually screws off to expose the thread, but on using some force I found the plugs do not have a removable cap, and destroyed both plugs by separating the core. 

Hello Re-Rider, sometimes the cap is sealed with the spark, for example Champion has 3 cap's type:

[usasmartindian]

Y - M12x1.25, 16 mm socket
R - With interference suppression resistor
7 - Heat range
M - see photo for dimensions
E - Nickel yttrium
S - 0.7 gap

Excellent information my friend. with this can nail down on the type. Even though something similar is available in NGK the terminal nut is fixed and cannot be removed. Is there any way we can just change the ignition coil wire for Meteor 350 to accommodate SP terminal nut. then lot of SP are available with these specifications.

[GSS]

Thank you. I have found 7-8 alternative plugs. A majority have a solid terminal instead of the threaded stud. It should be pretty easy to change the spark plug cap to match the plug.

[usasmartindian]

Can anyone here post how to change the ignition coil wire suppressor cap to the SP. We have quite a few alternatives to the Bosch YR7MES plug in NGK, Champion, etc. Is there any way we can just change the wire with suppressor cap cable to spark plug or just the suppressor cap alone. I saw some online where they have a push screw type suppressor cap that can latch on to the terminal nut of SP.

[xpop]

Can anyone here post how to change the ignition coil wire suppressor cap to the SP. We have quite a few alternatives to the Bosch YR7MES plug in NGK, Champion, etc. Is there any way we can just change the wire with suppressor cap cable to spark plug or just the suppressor cap alone. I saw some online where they have a push screw type suppressor cap that can latch on to the terminal nut of SP.

Hello, as I can see the wire is not separable from the coil, but perhaps the cap is separable from the cable. Often the cap is screwed to the cable.

[Dexter]

Unless there is a problem with the Bosch plug, I would leave it alone. Disconnecting the cap from the HT lead to replace with a new cap may lead to other problems and if a warranty issue came up, you may be denied because of the tampering.

Bottom line, if it ain't broke, don't fix it.

[Bilgemaster]

I have searched using Torch and got no where.

What I know about 'Torch' brand spark plugs is that the very first commonly-recommended way of coaxing a generator from the Far East to run better is to yank out its Torch, Bongodongo or whatever other OEM plug they came with, replace that with its Champion, AC Delco, NGK or other brand name equivalent, and perhaps then use the Torch as a fishing weight.

Anecdotally at least, with my pair of little 2-stroke 900 Watt Harbor Freight primitivo fussbucket gensets that came with Torches, I can confirm this notion. After their swap to Champions both gensets immediately began starting MUCH easier and just seem to run happier and steadier and even a bit quieter, without all the previous "seeking". This has actually been noticeable and even measurable in their far more even power output too as measured both with a digital multi-meter used to fine tune their idles under load and hence voltages, and also on board my boat with its analog AC meter for shore power. Its needle no longer sways like a metronome.

So yeah, if I had a Meteor I'd be very happy to find an equivalent replacement for a Torch plug.

[usasmartindian]

Folks, had been to the dealer for specific concerns on my fuel gauge incorrectly showing up levels. They indeed found the problem and waiting to get the gauge replacement part. During that time I asked them if we could use a different spark plug and plug cap. They showed me the plug cap is easily removal as its a screw type threaded to the ignition coil. They suggested me to get a replacement threadable plug cap that can take in loose or solid terminal nut plug cap from NGK or any NAPA store.

Now this opens up plethora of spark plugs now that can be used that are much better the stock provided. I was suggested NGK (4288) PLKR7A Laser Platinum Spark Plug that has the same dimensions of the current torch/chinese bosch made plug YR7MES. This is available on amazon.com for $12 with tax and is the perfect fit but solid terminal nut. I have read great reviews on this SP and waiting to get it. Keeping you guys new information received.

[Dexter]

Folks, had been to the dealer for specific concerns on my fuel gauge incorrectly showing up levels. They indeed found the problem and waiting to get the gauge replacement part. During that time I asked them if we could use a different spark plug and plug cap. They showed me the plug cap is easily removal as its a screw type threaded to the ignition coil. They suggested me to get a replacement threadable plug cap that can take in loose or solid terminal nut plug cap from NGK or any NAPA store.

Now this opens up plethora of spark plugs now that can be used that are much better the stock provided. I was suggested NGK (4288) PLKR7A Laser Platinum Spark Plug that has the same dimensions of the current torch/chinese bosch made plug YR7MES. This is available on amazon.com for $12 with tax and is the perfect fit but solid terminal nut. I have read great reviews on this SP and waiting to get it. Keeping you guys new information received.

Use caution when buying these, or any plugs on Amazon, eBay, etc. Lots of fake plugs for sale under the NGK brand name.

Of course, the dimensions of the plug are important, but more important is the heat range of the plug. It seems most buyers of this plug own Mercedes cars, and those engines operate at lower temperatures than our air cooled engines. This plug may be hotter than the OEM Bosch plug.

https://www.diycarserviceparts.co.uk/blog/2019/09/19/how-to-avoid-counterfeit-ngk-spark-plugs/

[GSS]

Got these for my Meteor…lots of good alternatives for using solid terminal plugs with these NGK caps.

[thelksharma]

Got these for my Meteor…lots of good alternatives for using solid terminal plugs with these NGK caps.

Were these direct fit? What's the part no of the spark plug, please?

Thanks

[tooseevee]

Were these direct fit? What's the part no of the spark plug, please?

Thanks

         Isn't it shown in his picture of the plug?:  LKR7AI

[GSS]

Apologies for the delayed reply. These were a direct fit.

Here are the part numbers.

[usasmartindian]

GSS, thanks for the part numbers. Few clarifications and helpful. The plug comes with .8mm gap. for Meteor 350 the specification is 0.7mm - 0.8mm. Did you adjust the gap or just used the OEM setting on the plug. Also, did you notice any difference on the performance post change in comparison to the OEM plug (torch one called Bosch). Appreciate your experience after installation. thanks!

[GSS]

The stock gap was within specs, so I did not make any adjustments. In general, I stopped regapping new plugs well over a decade ago, as this truly makes no perceptible difference with current electronics. Engine starts and runs flawlessly, so no change from baseline. Won’t have a proper assessment until after it warms up below freezing in April.

[usasmartindian]

GSS/Others,

Got the NGK spark plug today and installed on my bike. Did not change the gap and installed using some anti seize. Turned on the bike and started with just a click. Rode the bike and it was smooth and quite peppy. Yet to drive for few miles as weather today was cold. Will edit and comment post my ride. Looked peppy and smooth post plug change.

[Dexter]

The stock gap was within specs, so I did not make any adjustments. In general, I stopped regapping new plugs well over a decade ago, as this truly makes no perceptible difference with current electronics. Engine starts and runs flawlessly, so no change from baseline. Won’t have a proper assessment until after it warms up below freezing in April.

Hi GSS,

So what was your opinion of the NGK plug and new cap you installed?

[MMRanch]

https://www.youtube.com/watch?v=cucE5cLoqOk

This might help ?    I'd like to go to the iridium myself !

[michiel]

The heat value of 7 from Bosch corresponds to a heat value of 6 from NGK.

[Dexter]

The heat value of 7 from Bosch corresponds to a heat value of 6 from NGK.

Yes, the NGK is a slightly colder plug, hence my request for GSS to report on how it performed.

Colder would be better than hotter, as long as it doesn't foul easily.

[ptclassic]

Any advantage of changing from the original spark?

[AzCal Retred]

The "fine wire" plugs have a lower gap-jump voltage because electrons have a proclivity for pointy surfaces vs. flat. The voodoo metallurgy keeps center electrode erosion to a minimum. With the thin center electrode, even as it wears and the gap increases over time, the gap voltage is still lower than for an equivalent standard plug.

Probably the biggest advantage is that the spark gap can be opened up a bit even with the standard coil, meaning there is a greater probability of a burnable mixture being between the electrodes and getting ignited when the plug fires.

OR - you can run the standard $4 plugs and toss them periodically when they crud up from oil wicking past the sloppy intake guide like I do on my PUB's. I'm guessing the "J" motor has actual intake guide seals and a better valve angle; if I had one I'd run the Iridium's "just because". The ones in my Toyota pickup had 100,000 miles on them and a gap of +0.070" (actually + 0.140", 2 plugs per coil) when they came out and still worked fine, but the Emissions test folks detected a slight misfire. Hard to beat NGK (No Good Kind... ) spark plugs.

[GSS]

Dexter and friends,
The NGK plug and cap have been functioning flawlessly. No noticeable difference compared to the OEM plug and cap, and wasn’t expecting any either.

The improvement with plug changes in the 500-535 cc REs used to be dramatic…not so much with current 350s, 410s or 650s, but I still have all switched to iridium plugs. Thanks.

[Dexter]

Dexter and friends,
The NGK plug and cap have been functioning flawlessly. No noticeable difference compared to the OEM plug and cap, and wasn’t expecting any either.

The improvement with plug changes in the 500-535 cc REs used to be dramatic…not so much with current 350s, 410s or 650s, but I still have all switched to iridium plugs. Thanks.

Thanks for your update! 

[usasmartindian]

Apologies for the delayed reply. These were a direct fit.

Here are the part numbers.

Hello recently I reviewing the mentioned part numbers. The plug cap comes with a 5kohm resistance and the mentioned sparkplug part number also comes with a 5kohm resistance. When used together it builds a 10kohm resistance. Logically the ignition coil has to send the voltage/current through a 10kohm resistance for the spark for the fuel to ignite. Logically in the past I have seen recommended resistance should be anywhere from 1k to 5k for any electromagnetic field to be nullified for other electronics. With such high resistance of 10k do you think we will be having efficient sparking at the electrode side for all the fuel to burn up.

Hypothetically most of the NGK spark plug caps come with a 5kohm resistance..dont you think its beneficial to use a spark plug with 0ohm to 1kohm to make it closer to the 5k ohm. If so is the case see NGK PLKR7A plug has a 1k ohm resistance compared to the one given here. Do anyone know the resistance values of Meteor 350 stock OEM plug cap and YR7MES sparkplug respective resistances?

[MMRanch]

Its my belief that the factory plug has to satisfy at least two parameters :

1.   Be good for all environments the bike will be used in.
2.   Not cut into the company's profit margin. 

Problem with that is simply :

1.   I don't live in the Desert , or the North of Alaska.

Its been my experience that , one heat range hotter will return better performance (and mpg ) when I can get away with using them  (Folks living on the Equator need not try it)  That would be in the Winter here in TN. USA.
Also
I like the Iridium plug .  I've read they are easier on the firing system and lasting longer ?? 

2.   I don't care if the plug cost $10.00 or more  . 
...........................


I hope NGK jumps to our rescue first !   

[Dexter]

I don't see the need for all this palaver over which plug to use when, as far as I have seen here, no one has complained that the Bosch plug isn't doing the job it needs to do. It's like pursuing the better mousetrap when the old standard still seems to do the job just fine.

When the Bosch plug starts to foul, or otherwise cause me grief, then I'll look for an alternative.

[MMRanch]

I FOUND THE SPARK PLUG CAP INFORMATION .   

https://www.ebay.com/itm/354376991819

Come to find out ...

The "F" in the product description is the key to the terminal type we are looking for .   
   
Interchange Part Number:   
8381Set4, 8381, LZFH

Personally , I want the non-resistor type so there is "less" to tear up.   They come in Resistor type too , but your on your own finding them !   

The Factory Cap is a strait type and - does screw off ... and on again too !! 
.................................

Now ... What is the Iridium plug I'm looking for ?   (prefer one heat range hotter) . 

[ptclassic]

I FOUND THE SPARK PLUG CAP INFORMATION .   

https://www.ebay.com/itm/354376991819

Come to find out ...

The "F" in the product description is the key to the terminal type we are looking for .   
   
Interchange Part Number:   
8381Set4, 8381, LZFH

Personally , I want the non-resistor type so there is "less" to tear up.   They come in Resistor type too , but your on your own finding them !   

The Factory Cap is a strait type and - does screw off ... and on again too !! 
.................................

Now ... What is the Iridium plug I'm looking for ?   (prefer one heat range hotter) .

Will replacing spark plug for a iridium will be lead to better performance in any way? for 20€ I could replace just for the fun..

[MMRanch]

? 

[longstrokeclassic]

If you’re replacing the stock plug with an iridium just for fun, then indexing it should bring forth copious amounts of undiluted hilarity 🤣

[MMRanch]

Always chasing the Elusive Amazing Unbelievable MPG !   

All the while ... Keeping up with traffic too !! 

Like your favorite puppy chasing cars or cats  ... we just have to do it !!!   

   

[ptclassic]

LOL


I'm wondering why here are trying to put an iridium spark.. my classic with almost 1year, only have less then 1000km. So I'm not looking for a better mpg, expecialy because I enjoy the sound it makes

I use the bike only in good weather and most of all, when I have time for it..

So if there no benefit replacing the original spark plug, only the bigger longevity of iridium, will keep the original

[Dexter]

LOL


I'm wondering why here are trying to put an iridium spark.. my classic with almost 1year, only have less then 1000km. So I'm not looking for a better mpg, expecialy because I enjoy the sound it makes

I use the bike only in good weather and most of all, when I have time for it..

So if there no benefit replacing the original spark plug, only the bigger longevity of iridium, will keep the original

Don't wonder the WHY of this thread, because there is no really good reason, except you may never have to change the spark plug for as long as you own the bike. Although, I have seen on other forums where those with too much time on their hands will change those out way too early too, just because. 

You've made a wise choice and saved a few Euros in the process. Even the RE owner's manual suggestion of replacing the plug at 12,000 miles is daft. With a cleaning and re-gapping at that time frame, it will easily do twice or three times that distance.

[sandeep88]

i recently replaced BOSCH YR7MES (OEM) with NGK LKR7BIX-P Iridium Max  in my RE Classic reborn ,engine sounds a bit louder & rough..

[ButteMT]

I just stocked up on the Bosch's.  Not 100% sure what if any replacements are good, so why mess around?  It's an odd plug so I think I'll play it safe.  A "performance" plug honestly even if it fits to me won't do jack squat for the bike!

Ride Safe 🙏🏼

[Dexter]

I just stocked up on the Bosch's.  Not 100% sure what if any replacements are good, so why mess around?  It's an odd plug so I think I'll play it safe. A "performance" plug honestly even if it fits to me won't do jack squat for the bike!

Ride Safe 🙏🏼

Quite true. A spark is a spark and longer life is really the only reason to use iridium.

[ButteMT]

Quite true. A spark is a spark and longer life is really the only reason to use iridium.

Given I'll likely do (based on today's mileage) less than 2k miles per year on it.  A few of the Bosch's will last me longer than I need to worry about.

I would wager most vehicles (cars+bikes) on the road have plugs that are shot, but still "work".
If you're even remotely attentive to changing/cleaning/gapping them, you'll be just fine!

Ride Safe 🙏🏼

[Tester177]

I have installed NGK Ruthenium RX Premium LKR7ARX-P on my classic 350 and changed the spark plug cap to NGK SD05E which is compatible with solid type terminals. The stability at low speeds seems to have increased and afterfire seems to have decreased.

I asked NGK in advance about installing Ruthenium spark plugs on the Classic 350. From them I got the plausible answer, "That spark plug is not for motorcycles and should not be used." I will use these spark plugs at my own risk.

[ButteMT]

Yep, why mess with something like that?  I'll stick with the YR7MES...

Ride Safe 🙏🏼

[Dexter]

I asked NGK in advance about installing Ruthenium spark plugs on the Classic 350. From them I got the plausible answer, "That spark plug is not for motorcycles and should not be used." I will use these spark plugs at my own risk.

I can't help but wonder why you even bothered to contact NGK, when it seems apparent your mind was already completely made up to use them? Their response to you is much like that yellow warning label on a step ladder NOT to use the top step to stand on, but you go ahead anyway and fall and break your head! 

[3oro]

Our NGK spark plugs are best if you don't use them sir

[ButteMT]

Our NGK spark plugs are best if you don't use them sir

[Grenouille]

New owner here from Phoenix, Arizona.
Just to make it a bit more exciting here on the topic of spark plug :
My 2023 Classic 350 here in Phoenix came with a...Champion RER6YCA / RLH00100.
I grew up riding 2 stroke moped, 125cc, 250cc...
The plugs would get fouled so quickly, you always carried a spare.
Nowadays, you don't need to worry about the plug anymore. And yet, maybe I have OCD, I always look for spares whatever I buy. As a matter of fact, I will soon open a Spark Plug shop from all the plugs I acquired over 40 years !!!
In the past week, I have learned so much. And the main thing, spark plugs for the Classic 350 is a fascinating issue all over the world. A fellow in Australia was telling me he paid $25.00 for one plug from is dealer. Now he buys them from india for $35.00 with shipping. Crazy nut!
The OEM Champion on my bike is "made in France". The spare RE plug the dealer sold me only say RLH00100 and is made in India.
SparkPlugs.com is a great source of information and supplies.
The "cap" at the end of a plug is called "a terminal". There are 3 kinds: non removable, screw only, screw with removal cap.
The OEM plug from RE is of the screw type. It seems not available here in the USA. The exact equivalent is the Champion RER6YC also made in France. But it comes with a non removable terminal, which is no problem if you just change the boot with a NGK one for example (about $5.00).
Champion makes the REA6YC with the screw type with removable cap, but the HEX (the size of the wrench needed for removal) is smaller than stock at 14mm. SparkPlugs.com told me it was the exact same specs as the stock one RER6YCA, and the smaller HEX size would do nothing.
I bought both kinds from them. And they are a perfect match and fit to the stock one. I paid $3.99 per plug.
For some reason, the OEM plug here in Arizona is colder than the BOSCH you guys have.
Bike runs great. And it is hot here. 108 today!
I couldn't find the BOSCH YR7MES here in the USA and it is a bit hotter than what came on my bike. Most plugs on Amazon are not legit. If you pay attention, the side of the plug with its # is never shown. It only says BOSCH. Some are even blank.
The Royal Enfield plug the dealer sold me as ZERO BRANDING. It just says on the metal part "RLH00100".
It seems that even Royal Enfield back in India has a hard time securing their OEM spark plugs, and that motorbikes coming out of the assembly line might have different plugs fitted.
If Royal Enfield has sold over 3 millions motorcycles in the past few years, why is there no exact match for their plugs from Bosch, NGK and Champion?
Sorry for adding to the confusion.

[ButteMT]

FWIW, I bought a bunch of YR7MES from a guy in TX on eBay.
I think I paid $12 each, which sucks, but given I won't be changing them often (I hope) it's fine.
Having some spares of the correct value makes me feel better, but I would like to know what other plugs, such as yours, are OK to use...

Ride Safe 🙏🏼

[WildCard]

Given I'll likely do (based on today's mileage) less than 2k miles per year on it.  A few of the Bosch's will last me longer than I need to worry about.

I would wager most vehicles (cars+bikes) on the road have plugs that are shot, but still "work".
If you're even remotely attentive to changing/cleaning/gapping them, you'll be just fine!

Ride Safe 🙏🏼

lol Iv done 2.7k in 3 weeks daily driver though.

[usasmartindian]

Folks thought of sharing my perspective. I did try NGK iridium and platinum in comparison to the OEM plug within RE supernova. Even though replacing them with a new boot to accommodate the solid terminal nut on NGK the bike ride was good and there wasn't much of a difference. Over few hundred to thousands of miles when I was checking the plug had a slight black coating around the plug itself and the tip was always brownish. Then I helped my friend who hadnt done much on his bike still having the stock plug did an oil change and inspected the plug the whole OEM plug even after 1500 miles was clean and soot free.

After seeing this replaced the stock plug cap and reinstalled my OEM spark plug in mine without changing anything much. The vehicle did everything the same and what freaked me out was the gas mileage I got for a tank. With the ngk's was getting around 76-80mpg's constantly and after re-installing the OEM YR7MES with stock CAP with same ride mode 50-60mph on Texas rds getting an astonishing 85-89mpg of the same fuel. Also see the engine running. What I learnt from this is let the beast run with what was installed and not be too particular on iridium or platinum. Spent $25 for both plugs but this puppy is happy with a low cost one. For probable reasons folks I think the heat range across the manufacturers play a vital role in performance of the plugs and the stock one seems to be performing better in my opinion. Don't change anything and just have a spare of the same. Not worth all the money spent.