Spark Plug Question

Superdriver

XS650 Addict
Messages
120
Reaction score
61
Points
28
Location
Comox B.C. Canada
I am currently using NGK BPR7ES plugs with a NGK resistor plug cap and Mikes XS Performance wires and duel coil.. I was thinking of changing to Champion plugs. Apparently, N7Y Champions are the cross reference to the NGKs. Does anyone have an opinion on the Champions or recommendations of a different Champion Plug to use. My bike is a 1978 XS 650 special. Thanks, Bill
 
I am currently using NGK BPR7ES plugs with a NGK resistor plug cap
No opinion on the plugs, but if you're running resistor plugs and caps, you're secondary resistance is too high.
You should run either resistor plugs or caps... but never both.
 
No opinion on the plugs, but if you're running resistor plugs and caps, you're secondary resistance is too high.
You should run either resistor plugs or caps... but never both.
Hi Jim. Thanks for your reply. I think I was using the wrong terminology in describing what I was using. When I said cap, I was referring to the plastic plug cover LOL This is my set up
 

Attachments

  • Cap.jpg
    Cap.jpg
    121.2 KB · Views: 71
  • caps 2.jpg
    caps 2.jpg
    85.8 KB · Views: 62
If the plastic cap is a resistance cap then you will have too much resistance in the system
I run non resistance wires caps and resistor plugs
I run AP63 plugs ( At first I didn't think they were resistor plugs but someone on this forum explained that they were) I was sure if there wasn't an R in the plug description it was non resistance )
 
Hi Jim. Thanks for your reply. I think I was using the wrong terminology in describing what I was using. When I said cap, I was referring to the plastic plug cover LOL This is my set up
Can't tell from the pic what cap that is. Have you measured the resistance of it?
 
Can't tell from the pic what cap that is. Have you measured the resistance of it?
It is a NGK cap. #LB05FP 5K OMS. Everything works great. No problems with spark. I was just thinking of changing to Champions as I have used them before in other bikes. Thanks and take care. Bill
 
Since it's a dual output coil, you have the secondary resistance, plus 2 5k plugs, plus 2 5k caps. There's 20k Ω's not counting the actual secondary at about 10-15k. That's too much resistance. Everything may be working great as you say, but it's still too much. Less tolerant to flooding... carbon buildup... who knows. Conventional wisdom says either resistor plugs or caps... never both.
 
I don't think Champions have the removable terminal nut, I think it's cast right on there. If that's true then your current caps won't fit on the Champions .....

NGK LB05.jpg


NGK makes a nice non-resistor cap but it won't fit on a terminal nut either, lol .....

NGK LZFH-New.jpg
 
Just because your seat of the pants says everything is working fine, doesn’t mean it is. IMHO, the simple solution is to continue using your NGK resistor plugs and replace the cap’s with NGK LZFH 8381. The OEM equipped the bike with NGK plugs. Why mess with that?
 
Since it's a dual output coil, you have the secondary resistance, plus 2 5k plugs, plus 2 5k caps. There's 20k Ω's not counting the actual secondary at about 10-15k. That's too much resistance. Everything may be working great as you say, but it's still too much. Less tolerant to flooding... carbon buildup... who knows. Conventional wisdom says either resistor plugs or caps... never both.
I meant 2 coils in one. It was part of the cam ignition upgrade i got from Mikes XS. Thanks for your reply. Bill
 

Attachments

  • coil.jpg
    coil.jpg
    77.5 KB · Views: 47
I don't think Champions have the removable terminal nut, I think it's cast right on there. If that's true then your current caps won't fit on the Champions .....

View attachment 235723

NGK makes a nice non-resistor cap but it won't fit on a terminal nut either, lol .....

View attachment 235724
Thank you for all that information. Champion caps are available. If I decide to change. Take care. Bill
 

Attachments

  • caps.jpg
    caps.jpg
    85.2 KB · Views: 44
Just because your seat of the pants says everything is working fine, doesn’t mean it is. IMHO, the simple solution is to continue using your NGK resistor plugs and replace the cap’s with NGK LZFH 8381. The OEM equipped the bike with NGK plugs. Why mess with that?
Hi Marty
Thanks for the info. I can easily stay with what I have and Upgrade to the cap you mentioned NGK LZFH 8381. I was just curious if anyone had any info on the quality of the Champions as a replacement for the NGKs. Take care. Bill
 
Many years ago, a buddy of mine worked at the local Honda shop. He told me all the new Hondas came with Champion plugs back then and they were junk. They would take them out and give them back to Honda by the bagful, lol, replacing them with NGK's. I don't know, maybe they've improved since then, but you really can't go wrong with NGK's. I've run them for years in pretty much all my bikes. In the late '70's when I got my 1st BMW, I stuck with the stock Bosch plugs for a while because I could get them dirt cheap out of the VW section in the JC Whitney catalog, like 69 cents each if I recall. But eventually, I decided to try some NGK's, since they had always served me well in my other bikes. Well, the BMW started easier, idled and ran better with them. Eventually I installed NGK plug caps too. I did the same to my Moto Guzzi when I got it - out with the stock Bosch plugs and in with NGK's, changed the plug caps too.
 
I meant 2 coils in one. It was part of the cam ignition upgrade i got from Mikes XS. Thanks for your reply. Bill
That's not 2 coils in one. It's a single coil with dual outputs. One primary and one secondary with 2 (floating) outputs on the secondary.
 
Many years ago, a buddy of mine worked at the local Honda shop. He told me all the new Hondas came with Champion plugs back then and they were junk. They would take them out and give them back to Honda by the bagful, lol, replacing them with NGK's. I don't know, maybe they've improved since then, but you really can't go wrong with NGK's. I've run them for years in pretty much all my bikes. In the late '70's when I got my 1st BMW, I stuck with the stock Bosch plugs for a while because I could get them dirt cheap out of the VW section in the JC Whitney catalog, like 69 cents each if I recall. But eventually, I decided to try some NGK's, since they had always served me well in my other bikes. Well, the BMW started easier, idled and ran better with them. Eventually I installed NGK plug caps too. I did the same to my Moto Guzzi when I got it - out with the stock Bosch plugs and in with NGK's, changed the plug caps too.
Thank you. The NGKs work fine in my bike. I guess I could upgrade to NGK Iridium plugs, and better caps ( NGK LZFH 8381) like Jim recommended and then leave it alone. The guidance I have received For my questions on this subject and others have been soo helpful. I'm sure glad I found this site. Take care. Bill
 
Thanks LOL. I'm still learning about this stuff. What does floating outputs mean? Thanks and take care. Bill
In a single output coil, one end of the secondary is grounded and the other goes to ground when it jumps across the plug gap... completing the circuit.
In a dual output, neither end is grounded (it floats). Jumping the plug gap on both ends completes the circuit.
 
In a single output coil, one end of the secondary is grounded and the other goes to ground when it jumps across the plug gap... completing the circuit.
In a dual output, neither end is grounded (it floats). Jumping the plug gap on both ends completes the circuit.
Fantastic. Thank you soo much. Take care. Bill
 
I don't find the need for the fancy, more expensive plugs. All I've ever used are the regular NGK's and they've always worked fine. I do change them out pretty frequently though, like every 3 to 4K. I find the center electrodes are beginning to wear down by then. The plugs still work OK but just not quite as well as new ones. I consider changing them a cheap "tune-up", lol.

It's hard to see the wear looking at a plug by itself. You need a new one to compare it to side by side .....

WornPlug.jpg


WornPlug2.jpg


Doing that, it's pretty easy to see the worn down center electrode on the old plug.
 
I don't find the need for the fancy, more expensive plugs. All I've ever used are the regular NGK's and they've always worked fine. I do change them out pretty frequently though, like every 3 to 4K. I find the center electrodes are beginning to wear down by then. The plugs still work OK but just not quite as well as new ones. I consider changing them a cheap "tune-up", lol.

It's hard to see the wear looking at a plug by itself. You need a new one to compare it to side by side .....

View attachment 235817

View attachment 235818

Doing that, it's pretty easy to see the worn down center electrode on the old plug.
I’ve been hoarding them as I find them. I’m also extending their miles.
 
Back
Top