tallcanuck
Member
Not looking to cause a fight. Genuinely asking advice on replacing my plugs. Manual says Bosch W7 DC but I’ve always been an NGK fan and I’ve read suggestion of NGKBP 5ES.
Opinions?
Thank you.
Opinions?
Thank you.
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Spark plug advice? Hopefully not a fight? Bosch or NGK on 1986 R80RT?
- Thread starter tallcanuck
- Start date
pauls1150
MOA #24991, south of Los Angeles
I know a lot of people use the W7DC, but my personal preference is generally NGK... cheap (especially if you compare to Bosch from a BMW dealer) and easy to get from your FLAPS.
btw, one of my NGK charts says W7DC equiv is the BP6ES, another shows the Bosch "6" & "7" heat range corresponding to NGK's "6" heat range (Snowbum's website agrees with this). Judge by the older plugs' color and the carb/exhaust setup...
A thread like this may get a lot of argument, but I doubt it actually matters much.
btw, one of my NGK charts says W7DC equiv is the BP6ES, another shows the Bosch "6" & "7" heat range corresponding to NGK's "6" heat range (Snowbum's website agrees with this). Judge by the older plugs' color and the carb/exhaust setup...
A thread like this may get a lot of argument, but I doubt it actually matters much.
Last edited:
GTRider
52184
As of this writing, you’ll find that NGK has joined most other sparkplug manufacturers in discontinuing production of non-resister plugs like the BP6ES. NGK’s charts show the replacement as BP6RES, which is a resistor plug (roughly 5k ohm, IIRC). I used to be able to get non-resistor plugs from Nippon Denso, another quality plug manufacturer, but they, too, have dropped the non-resistor plugs.
Problem is, airheads like your bike were all designed to use non-resistor plugs and plug wires that had 5k ohm resistance built into the plug cap. That helped suppress electrical interference from the ignition, so the bike’s sparking wouldn’t interfere with nearby radios and such. So adding a resistor plug to your existing resistor wires ends up with excess resistance in the ignition system.
We used to be able to get around that by replacing the OEM caps on the plug wires with 0-ohm NGK sparkplug caps, and system resistance was thus the same. Unfortunately, NGK has also discontinued production of the 0-ohm non-resistor sparkplug caps, and I have yet to find a replacement.
Bottom line is, your best bet right now is to swallow hard and buy the Bosch W7-DC series plug sold by your BMW dealer—apparently Bosch is still producing the non-resistor plugs for BMW. And lastly, there will be voices chiming in here about buying BP6ES or Bosch W7DC plugs on Amazon or FleaBay, but caveat emptor—there are a lot of fake plugs being sold through those vendors.
Best,
DeVern
Problem is, airheads like your bike were all designed to use non-resistor plugs and plug wires that had 5k ohm resistance built into the plug cap. That helped suppress electrical interference from the ignition, so the bike’s sparking wouldn’t interfere with nearby radios and such. So adding a resistor plug to your existing resistor wires ends up with excess resistance in the ignition system.
We used to be able to get around that by replacing the OEM caps on the plug wires with 0-ohm NGK sparkplug caps, and system resistance was thus the same. Unfortunately, NGK has also discontinued production of the 0-ohm non-resistor sparkplug caps, and I have yet to find a replacement.
Bottom line is, your best bet right now is to swallow hard and buy the Bosch W7-DC series plug sold by your BMW dealer—apparently Bosch is still producing the non-resistor plugs for BMW. And lastly, there will be voices chiming in here about buying BP6ES or Bosch W7DC plugs on Amazon or FleaBay, but caveat emptor—there are a lot of fake plugs being sold through those vendors.
Best,
DeVern
tallcanuck
Member
Wow thanks DeVern!!
I had no idea.
Thanks again.
I had no idea.
Thanks again.
pauls1150
MOA #24991, south of Los Angeles
melville
Member
Try Green Spark Plug Company in the UK. I was able to get Bosch non-resistor plugs for about $4/each. Took a couple weeks to get here. I'll bet they have NGK available also, I'm just a Bosch snob. I bought 8 plugs (enough to set up my dual-plugged R100/7 and have the next set ready to go) and shipping was about $9.
tallcanuck
Member
wow thank you!!
tallcanuck
Member
Melville
Thanks for telling me about green plug spark company. Six Bosch w7dc plugs shipped to Canada for 50 bucks which is pretty good.
Thanks again!!!!!
Thanks for telling me about green plug spark company. Six Bosch w7dc plugs shipped to Canada for 50 bucks which is pretty good.
Thanks again!!!!!
