Author Topic: Spark plug resistance (Read 14823 times)

woodgeek · « **on:** February 17, 2018, 02:44:02 AM »

I pulled the original plugs from my K and they looked pretty good after I cleaned them up. On a whim I measured their resistance. Three looked good, measuring between 5.2 and 5.8k ohms. But the number 2 wire measures 9.3k ohms. Guess I need new wires. Bummer. I had to order new coils because my original 2/3 coil measured bad. Wonder if the high resistance of the #2 wire helped kill it. 🤷‍♂️

As an aside, the previous owner was running X5DC with these wires. The equivalent of NGK D8EA. They look brand new after 18 years not being used. [emoji23].

Laitch · « **Reply #1 on:** February 17, 2018, 08:09:51 AM »

Quote from: woodgeek on February 17, 2018, 02:44:02 AM

They look brand new after 18 years not being used. .

What did the gaps measure?

woodgeek · « **Reply #2 on:** February 17, 2018, 01:02:49 PM »

Quote from: Laitch on February 17, 2018, 08:09:51 AM

What did the gaps measure?

I’ll check this evening

Filmcamera · « **Reply #3 on:** February 17, 2018, 03:32:01 PM »

I just installed some of those Bosch X5DC's myself along with some new power leads from BSK Speedworks. I have not done any real miles yet but so far they both feel good.

Inge K. · « **Reply #4 on:** February 18, 2018, 06:14:33 AM »

Quote from: Filmcamera on February 17, 2018, 03:32:01 PM

I just installed some of those Bosch X5DC's

You should use spark plugs with resistor (XR5DC) on the 4V models.

Filmcamera · « **Reply #5 on:** February 18, 2018, 06:41:13 AM »

Ah really? Good to know, thanks, I will get some. These 4v bikes really are very different animals to the 2vs aren't they?

The Mighty Gryphon · « **Reply #6 on:** February 18, 2018, 09:19:31 AM »

Are the new spark plug wires resistor wires? If they are you can probably use non-resistor plugs. If not, you need the resistor plugs as Inge says.

Inge K. · « **Reply #7 on:** February 18, 2018, 09:31:18 AM »

4V models have two resistors in the wires (5K + 1K ohm) and is also using resistor spark plugs.

The Mighty Gryphon · « **Reply #8 on:** February 18, 2018, 09:47:32 AM »

Thanks, Inge! I didn't know that. Aways thought that the 4V engines had straight wires with resistor plugs.

Is there anything about these bikes you DON'T know???

Inge K. · « **Reply #9 on:** February 18, 2018, 11:16:45 AM »

Quote from: The Mighty Gryphon on February 18, 2018, 09:47:32 AM

Thanks, Inge! I didn't know that.

Not so shure about that.........

http://www.motobrick.com/index.php/topic,8207.msg61638.html#msg61638

Filmcamera · « **Reply #10 on:** February 18, 2018, 11:30:49 AM »

Honestly I am not sure if the new leads are resistor leads or not. I do know that BSK speedworks ask you to specify 2v or 4v or K1100 when you order so they must be different leads. They also come with nipples.

I just did a 90 mile ride to the beach and back just because it is Sunday morning and the bike felt great. Still I have ordered and will fit the resistor plugs and report if I feel a difference.

Inge K. · « **Reply #11 on:** February 18, 2018, 12:01:37 PM »

Quote from: Filmcamera on February 18, 2018, 11:30:49 AM

and report if I feel a difference.

You won't.......but having a lower resistance than what the ignition system is designed for can damage
the coils and output transistors in front of the battery tray.....that is when using to low resistance
over a longer time.

Filmcamera · « **Reply #12 on:** February 18, 2018, 01:11:49 PM »

I emailed BSK and to my surprise they have already answered me!

They said

Quote

they have the required built in resistance and so you should use the recommended plugs for the bike.

So I will install the XR5DC plugs when I get them

Filmcamera · « **Reply #13 on:** February 18, 2018, 05:37:26 PM »

OK now I am just getting confused...

It seems that, according to Clymers, the 1991 K00 16v uses the X5DC not the XR5DC

rbm · « **Reply #14 on:** February 18, 2018, 05:58:35 PM »

Clymers might be wrong. BMW OEM manual for the K1100 says otherwise:

Filmcamera · « **Reply #15 on:** February 18, 2018, 06:00:36 PM »

Cylmers says the XR5 for the 1100 as well but the X5 for the K1 and K100 1990 on, I think I will put the XR's I ordered on when they arrive nonetheless.

Inge K. · « **Reply #16 on:** February 18, 2018, 06:04:17 PM »

Both the owners manual and ETK specifies Bosch XR5DC for the K1 and K100RS4V.
I put more trust in BMW than Clymer.
PS. K1100 using Bosch XR7LDC (double ground electrode).

Filmcamera · « **Reply #17 on:** February 18, 2018, 06:06:02 PM »

XR5DC it is! Thanks

rbm · « **Reply #18 on:** February 18, 2018, 06:08:28 PM »

Probably too late to the party but I found a softcopy of my 4V OEM manual. Inge is correct ... XR5DC.

Filmcamera · « **Reply #19 on:** February 18, 2018, 06:12:13 PM »

Confirmation is always welcome RBM and hopefully others in the future can be helped as well, thanks again to everyone.

Inge K. · « **Reply #20 on:** February 18, 2018, 06:16:52 PM »

A slightly better copy:

Laitch · « **Reply #21 on:** February 18, 2018, 06:50:55 PM »

Quote from: Inge K. on February 18, 2018, 06:04:17 PM

Both the owners manual and ETK specifies Bosch XR5DC for the K1 and K100RS4V.

They're even suitable for the little ones, bless their hearts.

Inge K. · « **Reply #22 on:** February 18, 2018, 07:15:35 PM »

You can't trust anybody these days.

The Mighty Gryphon · « **Reply #23 on:** February 18, 2018, 10:00:45 PM »

Quote from: Laitch on February 18, 2018, 06:50:55 PM

They're even suitable for the little ones, bless their hearts.

That seems to agree with what I was told by the service tech at NGK, that is that a resistor plug can be used with no ill effect in place of a non-resistor plug, but that you can't go the other way. Apparantly the only downside to the resistor plug is that a tiny bit less energy is available in the spark. Makes me wonder why they even make non-resistor plugs.

Laitch · « **Reply #24 on:** February 18, 2018, 10:15:25 PM »

Quote from: The Mighty Gryphon on February 18, 2018, 10:00:45 PM

Makes me wonder why they even make non-resistor plugs.

They're used when resistance is futile.

News:

Author Topic: Spark plug resistance (Read 14823 times)