Sparks plugs for 91 K100RS

[Mudbug]

I started doing my own routine maintenance. I go by the maintenance schedule in the owner's manual, 5,000/10,000. So I went to my local BMW dealer and purchased the parts for the 10,000 maintenance.

I noticed that the spark plugs that he sold me were Bosch XR7LDC for over $10 a piece ( ouch ). The owner's manual states Bosch X5DC. I found an on-line source for the Bosch X5DC, $19.50 for 4.

Three years ago, the dealer put the X5DC for a 10,000 maintenance. He says X5DC, BMW part equivalent, are no longer available. Yet I found the Bosch on line at the beemerboneyard.com who states that the X5DC are for K100 2 valve engines.

My question is, do I use the X5DC for my 4 valve 1991 K100RS or do I use the XR7LDC?

 

[PHMARVIN]

Hi, Mudbug,
I don't know what originally came in your '91 K100RS. I have had 2 K1100LT's and my wife has a K75 and has had 2 other K75's, so I have experience with both 2 and 4 valve K-bike motors'

The 2-valve motors left the factory with Bosch X5DC spark plugs and the K1100LT's left the factory with XR5DC plugs. A few years ago BMW changed the spec for the K1100LT from XR5DC to XR7LDC, the OEM plug for the K1200RS in 1998.

I refuse to be robbed of over $10 per plug by the dealer. Based on advice by the late Rob Lentini, I began using the Autolite 4163 plug (about $1 each from Checker/Kragen/CSK) in the K1100 bikes and later in the K75's. In over 100k of use in both 2- and 4-valve K-bike engines, I never had any problems with the Autolite plugs.

 

[HFbmw]

spark plugs

Figure its time for me to buy plugs. Thot about after market ones, cheaper price for sure. However the Bosch I have in the bike now... well they are the same ones that was there when I bought this bike 4+years ago or 83,000 miles.
I know, one is supposed to run to the dealer and buy plugs every 12,000 miles. hmmm.
So I am thinking of staying with the original type plugs... being I have missed buying plugs ... lets see 7 times?

take care,

tim lindstrom
91k100lt 136,000+ miles

 

[BUDDINGGEEZER]

Spark Plugs

I bought a set of Bosch X5DC plugs from Beemer Boneyard to put in a K100 LT. PO said he had installed NGKs and the bike has run great for 7000 miles, so I have waited to change.

I just bought a K75 with new NGKs and the bike missed terribly. I took 3 of my Boschs and installed in the K75. It now runs great. I don't know if the NGKs were bad. The bike would not start when I bought it because the mass airflow sensor was not in its boot. Maybe the repeated attempts to start the bike fould the NGKs.

I see the spark plug boots on both my Ks have a 5ohm resistance caps. I assume that is why the XR5DC plug is not recommended. Usually the R means resistance plug. Electronic ignitions need plug resistance. Some manufactures solve this with resistance caps, some resistance plugs. If one uses a resistance plug with a resistance cap you usually have reduced plug fire due to too much resistance= reduced performance.

If a comprable brand plug in the proper reach, resistance or not, and heat range costs less and the bike runs good on them, why pay more?

Ralph Sims

 

[saltdog]

salvage parts source??

Can anyone direct me to reputable salvage part sources??

Thanks, New to MOA, BMW rider since 1988 but took 12 year off

1993 K1100RS

Need Front fork brace and all hardware and brake tubes from fender to calipers etc

have what appears to be K1 brace

Thanks again
saltdog
Memphis TN

 

[BUDDINGGEEZER]

Used Parts

I have bought several items form Phillip Engel @ Engeland European Motorworks. 704-562-1713. He has an Ebay store and his own website also. Just Google his company name. The website has a toll free number.

Also I have bought from Beemer Boneyard www.beemerboneyard.com.

Both are outstanding. Engel has a lot of K bike stuff.

Ralph Sims

 

[mrich12000]

Ya Phill is great and he answers your email.

 

[cayuse60]

Ya Phill is great and he answers your email.

...and will call you if there is any issues