Members Rides


Members Rides

NField Gear

40 Guests, 1 User
Welcome, Guest. Please login or register.
Did you miss your activation email?
May 31, 2016, 02:58:00 am

Login with username, password and session length


Author Topic: Spark plug health  (Read 3271 times)


  • Grand Gearhead
  • *****
  • Posts: 5,794
  • Karma: 2
  • "But it's a dry heat here in Arizona
Re: Spark plug health
« Reply #30 on: June 19, 2013, 05:33:22 pm »
It's possible the 10 percent ethanol used in our fuel is contributing to the problem.
It certainly can and does cause other problems with other parts.

I've used Bosch spark plugs in the two Mercedes I've owned and they seemed to work fine, but they were the single electrode style.

I am surprised that you saw no difference when you used the NGK BPR6ES plug but as you say, your Bosch was working fine.

In my case, my new RE G5 was having misfires at idle speed and when just cruising at a steady 40-45 mph (65-73 kmph).  Changing to the NGK totally eliminated those issues.
2011 G5 Deluxe
1999 Miata 10th Anniversary

no bs

  • Grease Monkey
  • ****
  • Posts: 486
  • Karma: 0
  • if it's got two wheels i'm on it
Re: Spark plug health
« Reply #31 on: June 19, 2013, 06:35:10 pm »
over the years we toyota mechanics have been pulling bosch plugs out of 22r/22re engines due to poor performance. people get them for cheap at the parts store and can't figure out why their "home tune-up " failed. as to the screw tips, the nd plugs we get from toyota don't come off. don't know why.
killing bugs since 1972 2011 g5 deluxe


  • Grease Monkey
  • ****
  • Posts: 288
  • Karma: 0
Re: Spark plug health
« Reply #32 on: June 20, 2013, 07:08:59 am »
I ran my electra EFI for about 1300 miles on the original Bosch plug.  The bike ran fine once warmed up, but was reluctant to idle from cold until the engine had run for a couple of minutes. I changed from the original Bosch to the recommended NGK, and the difference when idling was like night and day. It will tickover from cold without help, and the tickover is generally much more even.

The other thing I noticed was that the Bosch plug (twin electrode one) looked far older than a plug that has covered only 1300 miles should. I have taken spark plugs out of my car after 10,000 miles that look better than it. From now on it is NGKs for this Enfield.
2012 Electra EFI Riviera Red
1954 Francis Barnett Falcon 70


  • Grand Gearhead
  • *****
  • Posts: 5,511
  • Karma: 0
Re: Spark plug health
« Reply #33 on: June 20, 2013, 11:27:54 am »
I changed my Bosch out at about 250 miles. The NGK was still good at 15,000 miles when I changed it because I had more. The idling was still uneven at first, but a lot better than the Bosch. It improved as the miles went on. It was a non issue after about 1500 miles.
2013 Moto Guzzi V7 Racer
2011 Black Classic G5 (RIP)
I refuse to tiptoe through life only to arrive safely at death


  • phaneropter
  • Grand Gearhead
  • *****
  • Posts: 762
  • Karma: 0
Re: Spark plug health
« Reply #34 on: June 20, 2013, 07:09:58 pm »
Thanks for the replies so far.

I'd like to know whether all who had issues with the Bosch plug run on ethanol added fuel (aka bio fuel i believe).
Eventually other suggestions for the malperformance.

I also understand that not allowing the engine to warm up as in start and ride off will cause erratic behaviour. It will then take longer than the regular 90 seconds for the ecu to get its bearings right, all the while running way too rich.
Although I cannot understand how this would lead to a different result in both plugs.

moriunt omnes pauci vivunt


  • Grand Gearhead
  • *****
  • Posts: 1,164
  • Karma: 0
  • 2012 Royal Maroon C5 Special
Re: Spark plug health
« Reply #35 on: June 20, 2013, 09:11:20 pm »
Most all the fuel in New Mexico is 10% ethanol.
I fill at a Chevron station, but there isn't a placard declaring the 10% dilution. It is well documented that the 10% dilution adversely affects power. The police here draw from their own reserve and refuse to add the ethanol because of that.

I changed out to a NGK plug just after the 300 mile service and there was a big improvement in idling and power.
Rather than have a homeless person for the holidays, I decided to stick with ham.