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Spark plug question (non resistor verses resistor)

Started by rdsarefun, June 22, 2023, 11:30:04 AM

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rdsarefun

Hi All,
I searched the forum for some definitive answers to my question and nothing detailed, so here goes.  A few years back I posted an article when I had my last RD (73 350), then sold it and am back in the game after selling my stash of spare parts.  I was running NOS NGK B8HS plugs in my bike without issue, everything that I see now seems to be a resistor type plug from NGK and sources online.  I have a stock ignition (soon to be upgraded to a Dyna S) with stock coils.  When rebuilding, I checked resistance of coils and within spec, and I believe the NGK caps that are on these coils add 5K resistance.  My question is what is the appreciable change from my old b8HS plugs (I actually have 2 left) to running a plug that is a resistor type? I ask as I like to have 2 new plugs in my tool kit so I don't get stranded with a fouled plug (happened in high school on my mint 70 purple and white R5, good thing is that I broke down in front of one of the prettiest girls in schools house and she let me keep it there for a few days till I got it sorted)  Regardless, if anyone could shed some light on this or pros/cons would be much appreciated.  Thanks

m in sc

run a non resistor cap with resistor plugs. will it run with resistor and resistor set up? sure. ive done it and had no appreciable or even notable loss but still not preferred. my .02

 

SoCal250

NGK discontinued the non-resistor plugs a few years ago so resistor is the only version available now. You can disassemble the plug caps, remove the resistor and replace with a small piece of metal. A section of brass #10 machine screw trimmed to about 18mm long works as a replacement. Or just buy non-resistor caps.
75 Yamaha RD125B   75 Yamaha RD125B (project)
75 Yamaha RD250B   75 Yamaha RD200B (project)
73 Yamaha RD350     77 Yamaha RD400D   79 Yamaha RD400F  
91 Yamaha TZR250R  89 Yamaha FZR400   05 Yamaha FZ6   
05 Yamaha XT225TC  82 Honda MB5  02 Aprilia RS250 Cup (sold)

Economy Cycle John

The NGK 5K and 0K 90 degree plug caps have also been discontinued.
www.EconomyCycle.com - RD/RZ Parts, Services, Tools, Accessories & Swag

m in sc

#4
what? no 0 k plug caps? wtf we supposed to use now? thanks for telling us, but fuck.  :huh:

edit: i just stocked up on some hearing this. like, a lot. lol.

Economy Cycle John

I have some alternatives on the way, nearly identical sans the NGK logo. And the VAPE wires/caps are 0k, copper core.
www.EconomyCycle.com - RD/RZ Parts, Services, Tools, Accessories & Swag

pidjones

Simple to turn many resistor caps into non-resistor by replacing the resistor with a section of #10 solid building wire.
"Love 'em all.... Let GOD sort 'em out!"

SoCal250

Quote from: Economy Cycle on June 22, 2023, 04:25:35 PMThe NGK 5K and 0K 90 degree plug caps have also been discontinued.
:eek: well that's no bueno!
75 Yamaha RD125B   75 Yamaha RD125B (project)
75 Yamaha RD250B   75 Yamaha RD200B (project)
73 Yamaha RD350     77 Yamaha RD400D   79 Yamaha RD400F  
91 Yamaha TZR250R  89 Yamaha FZR400   05 Yamaha FZ6   
05 Yamaha XT225TC  82 Honda MB5  02 Aprilia RS250 Cup (sold)

Economy Cycle John

www.EconomyCycle.com - RD/RZ Parts, Services, Tools, Accessories & Swag

Djg8493

Also note NGK still sells B8HS-10, they are for the marine market and are the same plugs just with a larger gap.  I bought a box of them, re-gapped them and have been running them for about a year with no problems. 
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6