K11 Owners Group

hockeyshifter · Posted: Wed Apr 30, 2008 1:30 am Post subject: what are your spark plugs?

i have done some searching on the board but have little to show for it.
i have found ac delco; bosch champion and ngk and a splitfire spark plug that is listed to fit the RS but what i want to know is what is the community using.

i would also like to find a plaitium plug that will fit any suggestion.
_________________
fix the problem not the blame ; fix what is messed up ; NO one is to blame.

jarnbak · Posted: Wed Apr 30, 2008 7:54 am Post subject: spark plug

I use denso ix22b(gap 0,9mm) or ix22(gap 0,8mm) on my k1100lt.It seems to help starting and idle.I replace the plugs after aprox.40000 km
with no adjustment between.Denso ix plugs are the iridium type.
regards Palle
k1100lt 92 170000km.

Scott_Anderson · Posted: Wed Apr 30, 2008 7:55 am Post subject:

I have used both NGK and Autolite in my LT. I didn't notice any real difference between them other than the Autolites were more readily available at my local parts outlets.

Ride safe.

Scott

Euripides

Friends: In my '87 K100LT I have had good luck with Bosch X5DC and NGK D7EA STANDARD type sparkplugs. (I DO NOT recommend Cham--n as they appear to be of lesser quality. The side electrode appears to be made of a thin, soft material and does not hold its setting. The center electrode appears to be made of a thin soft material and wears fast.)

However, I caution against using small diameter center electrode sparkplugs, platinum or otherwise, in any engine that has a "wasted spark" ignition system. The K100 uses this type of ignition system; the K75 does not. In a wasted spark system, 1/2 of the sparkplugs are firing in normal polarity and 1/2 are firing in reverse polarity. In normal polarity, the spark jumps from the center to the side electrode; i.e. the center electrode is negative respective to the side electrode which is positive. Electrons flow from negative to positive. Reverse polarity means just the opposite; that the spark is jumping FROM the negative side TO the positive center electrode.

The K100 uses two coils to fire four cylinders and the two sparkplugs of each 360 degree firing order cylinder pair are connected in series through their respective ignition coil. In the K75, a dedicated ignition coil is used to fire each seperate sparkplug and each plug fires in normal polarity so the problem is not systemic to the K75.

In a wasted spark system, since the sparkplugs from those two cylinder pairs that are 360 degrees apart in the firing order, are connected in series through the high voltage secondary winding of their ignition coil, both plugs fire simultaneously. One sparkplug always fires in a normal and the other always fires in a reverse polarity mode. Also, one of the cylinders will always be on the compression and one will always be on the exhaust stroke. Therefore, the exhaust cylinder spark is "wasted"; i.e. does not fire the fuel air mixture. This is why this system is called "wasted spark".

Sparkplugs using a very small center electrode, platinum or otherwise, are a known problem in wasted spark systems. This problem of misfiring occurs more frequently after the plugs have been run for a while and deposits have formed on the center electrode; thereby making it harder for the negative charge to find its positive target.

However, the Bosch "super" (standard type) and the standard type NGK sparkplugs have large center electrodes and have run well in my K100 engine. I recommend those two brands. (The ND and Denso Brands may be ok, but I have no source of supply for those and have not used them. Autolite plugs may be ok but I avoid them because the shell is not plated. It soon forms a layer of rust which looks unsightly.)

In summary, my warning is specifically aimed against using any spark plug with a very small center electrode in a wasted spark ignition system. Unfortunately, the Bosch Platinums are of this type.

Best Regards - Euripides

DetroitDan · Posted: Wed May 07, 2008 11:49 am Post subject:

"Double-platinum" plugs were designed specifically for wasted-spark systems.

You're right on target about single platinums. They transfer metal on the reverse-polarity plug.
_________________
1973 CB350F / 1977 R100/7 / 1991 DR650S / 1995 K1100RS

"No man in the wrong can stand up against a fellow that’s in the right and keeps on a-comin’” Capt. Bill McDonald (1852-1918)

Euripides

Dan: Thank you for that information as I was not aware of that. Question: What is a "double platinum" spark plug and how does it differ from a "regular platinum" plug? - Euripides

dave n · Posted: Wed May 07, 2008 12:48 pm Post subject: spark plug nivana again

K.I.S.S. - keep it simple and cheap - AUTOLITE 4163 plug - gap @ .025 good for at least 20k - $1.00 ea anywhere !

You don't need those fancy plugs !!!
_________________
Dave Norris KOG 248
1999 Cagiva Gran Canyon
1993 K1100LT w/Hannigan sidecar
2008 Suzuki DR650

Flying Duck · Posted: Wed May 07, 2008 12:57 pm Post subject:

I ran the Autolite 4163s in my K100RS4V - seemed fine to me. Those seem to wear out a little faster than Bosch so I think 10k is better than 12k for the change interval - and that also synchs up nicely with changing Mobil 1 every 10k.

A while back I bought a lot of 20 XR5DC Bosch plugs on Fleabay so that's what I run in my K1100s. At some point BMW changed the recommended plugs from the XR5DC to the XR7DC so that's all BMW sells now I believe.

I run the XR5DC plugs because they run cooler than the XR7DC plugs and I figure that since most of my riding is LD touring I'm better off with the cooler plugs. Someone please straighten me out if this is flawed logic for running XR5DC plugs.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Euripides

Dear Flying Duck: Unfortunately, that may be flawed logic. The proper heat range for your K1100 should be determined scientifically by carefully examining the plug electrodes immediately after about a 100 mile trip that meets your typical style of riding. Simply picking a heat range because you may think it is correct is guessing. - Euripides

Flying Duck · Posted: Wed May 07, 2008 2:45 pm Post subject:

Well, that was what BMW sold for the bike up until 97 so thay can't be THAT bad, right? Question

_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Euripides

Dear Flying Duck: Unfortunately, you are assuming that the operating perameters that BMW used to develop the factory recommendation for a typical spark plug heat range for the K1100 the factory tested years ago would be the exact same perameters that would apply to your K1100 and your driving conditions today. This is flawed logic. I believe that you would be better served by visually examining the plugs under your exact operating/ touring conditions and select a heat range based on your visual examination of the spark plug electrodes. - Euripides.

acftfliehr · Big Brick Rider Joined: 05 Nov 2007 Posts: 62

I had a Champion center porcelain blow out completely from its metal shell on a hot ride on the K100 in 1986 up in the Sierras of California.

Fortunately I carry a set of used plugs (habit from my TM400 dirt bike days) which got me going...

I still have that piece of S#@t Champion metal case that is just the threaded portion minus the center electrode and porcelain...

Amazing the combustion chamber/valves weren't damaged.

DetroitDan · Posted: Sat May 17, 2008 6:23 pm Post subject:

CheapJapCopy · Posted: Sun May 18, 2008 3:36 pm Post subject:

This is an eye-opener of a thread.. I was just using the Bosch ones they recommend. Any other thoughts from people?
_________________
1992 K1100RS - Red and gold.