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Discussion Starter #1
So I thought I would ask some of you guys that are more motor builder/gear heads than I am, what you think. When I bought my '17 RK, I had the dealer put the SE Stage IV Kit in it so it's covered under the 5 year warranty plan I bought. After they finished the build, I asked what plugs they put in it. They said the stock HD Plugs would be fine for that motor. The reason I question that is because when I had a local race builder tune my '03 RK with a Stage III Kit in it, he told me that he changed out my old plugs to a set of colder plugs because of the BB Kit and Cams. (I'm almost positive he said colder..... they are Autolite 4162 plugs). It makes sense to me that you would want to run a different plug other than stock on a non-stock motor. Anyhow, would you run just stock plugs in my new M8 or something else? I already know about "Oil Thread-esque" debate over regular spark plugs vs Iridium vs something else, and that's not what I'm asking. Just wondering about hotter vs colder vs stock in this application. Thanks for the input fellers.
 

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Not a builder but I was always taught that what matters is what they look like. If theyre creating a strong clean burn they are the right plugs. Otherwise its a matter of fit.

Heres what NGK says: HOW DO I CHOOSE THE RIGHT SPARK PLUG?
A: There are several factors—such as thread reach, thread diameter, the insulator nose projection and whether the spark plug incorporates a gasket or is of the conical type—to consider when choosing the correct spark plug for your needs. If you have a stock factory vehicle, just click here to use the Part Finder and follow the prompts to find the appropriate plug for your needs. You can also ask specific questions here - [email protected].

In most cases, it is not until the engine is modified, or the compression is raised significantly, that stock ignition systems and spark plugs begin to show signs of being inadequate. At this point, a variety of factors determine which spark plug will be best suited for a particular configuration. In these modified engines, specific electrode/tip combinations, electrode materials and colder heat ranges can provide measurable gains in power. If your vehicle has had extensive modifications, it would be best to seek the advice of the manufacturer of your vehicle, the aftermarket supplier who manufactured your modifications or your service technician
 

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If different spark plugs would be required with the kit the MoCo would have supplied them. The ECM has a system that measures spark duration based on the stock OEM plugs, it's called "ION sensing circuit".
On the EFI H-Ds a clean white to grey insulator would indicate a proper AFR. On carbed models a clean tan to brown is ideal.
 

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It probably comes down to what the kit contains...if a higher compression is added...coming from cam change...piston change ...or both...typically a colder plug would be installed to help pull heat away from the combustion chamber to reduce chances of knock

A hotter or colder plug only helps pull heat away from the chamber..and has nothing to do with how hot the spark is
 

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Discussion Starter #7
It probably comes down to what the kit contains...if a higher compression is added...coming from cam change...piston change ...or both...typically a colder plug would be installed to help pull heat away from the combustion chamber to reduce chances of knock

A hotter or colder plug only helps pull heat away from the chamber..and has nothing to do with how hot the spark is
The M8 SE Stage IV Kit comes with 11:1 High Compression Pistons and the SE 8-515 Cam...... this is kinda why I was raising an eyebrow. My inexperience and lack of hard core hot rod motor building makes me want to lean towards a colder plug, just like my Indy did with my '03 RK BB Kit. I understand that the ION sensing circuit comes into play with the ECM, but surely there is a colder plug that will still satisfy the ECM for this and yet still work better with the Kit I have than just the stock plugs...... or at least I was hoping so. I have noticed on hot days while riding 2 up and pulling up a hill, if I hit the throttle some, it'll start to kinda ping a bit, or at least that's what it sounds like to me. I thought about dumping a little Octane Booster in the tank as an experiment to see if it goes away but just haven't done it yet. Would a colder plug possibly fix that as well? Or is that a topic for a different thread, lol!
 

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Yes I have a 2017 rhs stage 4 and it pings alot really badly when it gets hot. I dont ride hard ,but I ride tank to tank on runs, in all rev ranges. I have full SE stage 4 and auto tune fueling cam and plate baker primary manual ajuster SE spark plugs it's been in out of dealer and on dyno twice.no one can fix it , can anyone help , I cant ride it anymore Bike ows me 60k au$ . Please how do I fix this. I just want to ride every weekend.
 

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I would go one heat range colder on plugs just to be safe. I doubt that will cure your problem though. You might get the spark retarded a bit and flood it with fuel. It might cure your problem or it might just wash down your cylinder walls :whoa

You really need to get it to someone who is well versed in tuning high performance engines.
 

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Yes I have a 2017 rhs stage 4 and it pings alot really badly when it gets hot. I dont ride hard ,but I ride tank to tank on runs, in all rev ranges. I have full SE stage 4 and auto tune fueling cam and plate baker primary manual ajuster SE spark plugs it's been in out of dealer and on dyno twice.no one can fix it , can anyone help , I cant ride it anymore Bike ows me 60k au$ . Please how do I fix this. I just want to ride every weekend.
You need a Good Tuner and a New Mechanic.
 

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Yes I have a 2017 rhs stage 4 and it pings alot really badly when it gets hot. I dont ride hard ,but I ride tank to tank on runs, in all rev ranges. I have full SE stage 4 and auto tune fueling cam and plate baker primary manual ajuster SE spark plugs it's been in out of dealer and on dyno twice.no one can fix it , can anyone help , I cant ride it anymore Bike ows me 60k au$ . Please how do I fix this. I just want to ride every weekend.
Seek out a good tuner in your area.
Troubles should disappear then.
It ain't the spark plugs.
 

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Not lugging it are we? Get the revs up a bit may help.
 
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