FJRiders.com

What kind of spark plugs are preferred for the FJR? Any that work better than others?

Is it possible to get platinum tipped ones for wear resistance?

Numbers would be appreciated if you have 'em.

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The plugs recommended in the user manual work fine for me.

Wheaton prefers the chrome ones with the crystal base. Bust says they retain the taste longer.

Dammit Marty, it's gonna take a while to unsee that ^^^^^

Ok in all seriousness...

Thanks Marty. I will be doing breaks, oil, and plugs this weekend.

How long have you ran those? Do you think they do better than the recommended 8K interval?

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Up yers Marty!!!!

silverback wrote: ↑Fri May 17, 2019 5:23 pm Thanks Marty. I will be doing breaks, oil, and plugs this weekend.

How long have you ran those? Do you think they do better than the recommended 8K interval?

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They're the only ones I run... and yes they will be fine well past 8K. In my experience.

I just today installed NGK 2306 CPR8EA-9. Standard plug. I replaced the factory originals at 13757 miles. The original were fine but i had them so i installed them.

Spininprop wrote: ↑Fri May 17, 2019 10:40 pm ...installed NGK 2306 CPR8EA-9. Standard plug...

@ Spininprop, your Gen III uses a different type plug than the OP's Gen I.

Iridium plugs have very fragile center electrodes. In theory you are not supposed to check the plug gap, just trust that the manufacturer set the gap correctly. If you do check the gap do not use a wire type gap tool, use a ramp type gap tool. If the gap does need to be adjusted use a side electrode bending tool that does not press on the center electrode.



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Modern motorcycles like the FJR aren't really sensitive to plug condition. It's a waste to replace plugs at 8k miles as the owners manual specifies, you can easily go double that with no street performance or mileage issues.

The Gen I and Gen II uses a waste spark ignition system, plugs 1 & 3 and plugs 2 & 4 fire together. Cyl #1 would fire on the power stroke and Cyl #3 would fire on the exhaust stroke at the same time, then Cyl #3 would fire on the power stroke and Cyl #1 would fire on the exhaust stroke at the same time. This results in Cyl #1 firing from the center electrode to the side electrode and Cyl #3 would fire from the side electrode to the center electrode. You can swap plugs 1 & 3 and 2 & 4 to get additional life because it will even out the electrode wear.

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The Gen I and Gen II have two ignition coils for the 4 cylinders. One end of the coil goes to Cyl #1 and produces an positive voltage and the spark jumps from the high potential center electrode to the ground side electrode. The other end of the coil connects to Cyl #3 and produces a negative voltage, the voltage is just as large as Cyl #1 except the voltage is negative. This causes the spark to jump from the side electrode to the center electrode which can be at -12,000 to -20,000 volts.

A new spark plug that has sharp edges on both the center electrode and side electrode will let a spark be initiated by roughly 12,000 volts. High voltage likes to concentrate on sharp points or sharp edges. If you could measure spark voltage of a new plug it would be 12,000 volts. As the spark plug electrodes erode and the edges become rounded it is harder to initiate a spark. Now coil voltage can build up to 20,000 volts before a spark is initiated resulting in delayed ignition. This is the symptom of a spark plug that is 'worn out'.

I have a 14. I will look I to the correct plugs. I like the platinum plugs so I don't have to replace as often. Motorcycles seem to be rougher on plugs and I am usually rougher on machines.

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The Gen3's have individual coil on plug, so we're going to assume the wasted spark era is over (I haven't tested that, but the signal comes right from the ECU). My original OEM plugs looked great at 20k, but since I was in there for valve check, etc. I replaced them with iridium CR9E1X... one heat range colder (seems to me iridiums run a tad hotter than conventionals).

silverback wrote: ↑Sat May 18, 2019 11:52 am I have a 14. I will look I to the correct plugs. I like the platinum plugs so I don't have to replace as often. Motorcycles seem to be rougher on plugs and I am usually rougher on machines.

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True in the old days m/c plugs didn't last long. With the 14, those days should be over (no wasted spark) and it won't matter much how hard you are on your machines, the plugs will last what they last. Ride more, worry less.

0face wrote: ↑Fri May 17, 2019 12:52 pm Wheaton prefers the chrome ones with the crystal base. Bust says they retain the taste longer.

Marty, are you sure those didn’t come off the ends of your handlebars?

We just took the plugs out of my 15 last month at tech day. I don’t know if they were original, but I bought the bike at 23K miles and the owner hadn’t checked the valves yet. So when we did them at 52K Ray inspected them and they looked pretty good to him if I recall correctly.

If folks are changing them at 8K, I would guess they have too much time and money on their hands.

Brodie wrote: ↑Sat May 18, 2019 9:47 pm

0face wrote: ↑Fri May 17, 2019 12:52 pm Wheaton prefers the chrome ones with the crystal base. Bust says they retain the taste longer.

Marty, are you sure those didn’t come off the ends of your handlebars?

No. I think he pulls them out of his ass. But handlebars is a good second choice.

I change my plugs religiously with regular plugs whenever I check the valves. At almost 100k miles I have not noticed any performance issues. Knock on wood.

It has been a long time since I have heard of this, spark plugs that are seized and snapping off when trying to remove them on the FJR. I have a 2012 with almost 60,000 miles and still running the same ones since the ODO had all zeros. I'm thinking about replacing them mainly out of some concern, if they aren't already sized, to try to prevent that headache and give the new ones a good treatment of anti-seize. Good idea or I shouldn't be concerned because it hasn't been a major issue?

If you do use anti-seize make sure to reduce how tightly you torque them! I used anti-seize out of that same fear but haven't on any subsequent set. Just be careful and don't over-tighten them and you should be fine. My last wet were in for almost 40k and came out easily enough.