Another spark plug thread

[Lou_TX]

Had some issues/hiccups twice in the last 2 weeks where the motor started intermittently cutting out. Hard to tell if it's just 1 cylinder or both at once. So I drained the fuel already (few months old), will clean the carbs again and use fresh fuel.
But I also checked the spark plugs. Both coated in black soot, probably from running it on the choke the last two times when she didn't even get to warm up. Maybe not. Will have to test further later.

My plugs are NGK BPR7E. I naturally tested the boots/caps as well. Measured with my ohm-meter, one showed right around 10 kOhm, the other close to 100 kOhm. Not kidding. Tested it 3 times, got measurements ranging from 80 to 105 kOhm. That sounds not only excessive but also completely wrong. Resistor plugs AND resistor boots? Too much. She always ran sluggish (for a 650), I wonder how much difference I see once I fix this problem.
FWIW, I forgot to measure the plugs themselves. NGKs are notoriously known for "working great when they work" and dying whenever they feel like. I am not the only one who's seen it firsthand. A lot of MC owners and mechanics can corroborate this.

So my question is: what is y'all's source for non-resistor boots/caps? I looked on Amazon, there are a few twist-on MC boots but they also have a few interestingly bad reviews. While I am leery of ordering something that could turn out to be a bad part, I also understand that Amazon has great return policy on defective items. But my question stands.

Heck, a second (bonus) question: would you go with the resistor plug and non-resistor boot or with the resistor boot and non-resistor plug? Trying to think ahead to the potential disappearance of resistor plugs in the future where they might be getting hard to come by (they are already overpriced compared to regular plugs).

Thanks in advance for any useful input.

 

[gggGary]

One or the other r plugs, caps. But they'll "work" together. Buy ngk caps. BP7ES are correct. BPR7ES will work with non resister caps. I'm big on cleaning plugs with a torch. The set in madness has been in (and out) there 10 plus years 20K miles. Still going strong. She's also got an accell coil that'd fire a plug in a bucket of oil..... Bout the only time I CHANGE plugs is getting rid of the wilfit plugs I nearly always find in my bargain barn bike buys.

 

[ckahleer]

Most resistor plug caps can be disassembled and the internal parts cleaned to get them back to their origional values.

 

[Wingedwheel]

I can’t remember where I saw it, either on here or another site, but the clip was about taking the resistor plugs apart and removing the resistance material. Seemed straightforward enough.

 

[Lou_TX]

I am definitely planning on cleaning the plugs with my torch once my neighbor returns it.
I will try to find the clip on how to disassemble the resistor boot because it did not seem like it can be opened up. I assume the insides might come out from the plug side but before I grab my needlenose pliers and destroy the boot, I'd like to verify. Hopefully I find something.

 

[MrBultaco]

Non-resister caps...
https://www.google.com/aclk?sa=L&ai...5zLnciUAxU3O0QIHRZnA1wQ5bgDKAB6BAgHEAs&adurl=

 

[Lou_TX]

Thank you.
As per online videos, the spark plug side comes out after unscrewing it with a flat head screwdriver. That rings a bell. Been a while since I played with boots. I might just eliminate the resistors (verify with ohm-meter) and run the resistor NGKs (which I still need to ohm out).
I will play with it after work, will post an update.

 

[Lou_TX]

Update: Nothing extraordinary. I tried disassembling the current boots but they are not serviceable for some reason.
So I grabbed a pair of boots from another bike, they too are 5k resistor boots. Both ohmed out correctly, as did the plugs. I installed them and she started and idled better, even after I took it off choke early, maybe 30 seconds. (normally I had to keep choke on for a while)
So yes, currently I have 5k plugs with 5k boots. That is not permanent, just for a test. I ran out of time to go for a test ride, maybe tomorrow.
In the meantime, I will be ordering correct non-resistor plugs and smaller resistor boots because the borrowed ones are pretty long and stick out too much.
So I should have another update maybe by the weekend.

 

[zrx1100]

Check out this thread https://www.xs650.com/threads/spark-plug-recommendations-stock-77d.67864/#post-872431

 

[JJames]

@5twins mentioned Volkswagen wires. Can't remember if they are resistor or not. My family has used the same set of plugs for three generations. Lol.

 

[Wingedwheel]

I bought a set of wires at Tractor Supply that had long enough wires for 3 bikes. If it’s good enough for farm equipment it’s good enough for the bike. lol

 

[jetmechmarty]

It’s my understanding that the NGK BP7ES spark plugs found on eBay and Amazon are counterfeit. I was able to find NGK zero ohm caps from another source. The last bike that came to me got zero ohm caps and BPR7ES plugs.

 

[Wagner73]

@5twins mentioned Volkswagen wires. Can't remember if they are resistor or not. My family has used the same set of plugs for three generations. Lol.

I believe he uses the EMPI VW silicone wires, and I seem to remember they are non-resistor.

 

[Its been a long time]

Because of NGK plugs being of doubtful provenance, I have switched to Denso plugs. I know it's possible to buy counterfeit Denso. But buying from a reputable local source over the counter I think is about the best I can do. Denso are available in resistor and non resistor types.

 

[Wagner73]

Because of NGK plugs being of doubtful provenance,

Disappointing when you have to watch out for inferior clones on just about ANYTHING!

 

[Its been a long time]

Disappointing when you have to watch out for inferior clones on just about ANYTHING!

Agreed. I avoid buying SKF bearings in the same way I avoid NGK spark plugs. In both cases, there's probably more fake product out there than genuine. So I don't take the risk.

 

[ckahleer]

Is there a chance NGK plugs bought from my local Napa store would be fake?

 

[5twins]

Yes, I use EMPI VW Beetle silicone wires, non-resistor with a stranded wire core .......

The wire kits for the Beetle come with 5 wires, enough for 2 1/2 twins, lol. I've been using these since the mid-90's on pretty much all my bikes.

 

[ckahleer]

New automotive resistive spark plug wire measures around 5K per foot. So the resistance to the plugs near the distributor may be under 5K and the longer wires may be over 10K. On a V8 engine, each cylinder is running wires with differant resistances.
I have no problem running 5K plugs with 5K plug caps on my motorcycles.

 

[jetmechmarty]

Is there a chance NGK plugs bought from my local Napa store would be fake?

Unlikely. Rock Auto has been tested as genuine as well. Most likely fakes are on eBay and Amazon.