BMW R1100 Spezifikationen PDF herunterladen (Seite 59)

NON-OEM (ORIGINAL EQUIPMENT MANUFACTURER) PLUGS

FOR THE R1100/850 OILHEAD - Rob Lentini

The BMW Internet lists have been ablaze lately over spark plugs! Why has a

simple item been such a popular subject of discussion? Here’s why…

Many of you are aware (sadly so!) of the surging that is common in many of the

R1100/850 series BMW Oilheads. This subject itself has been one of much

discussion and I took some time to investigate it myself on my personal ’94

R1100RS. My work led to my four part series on “R1100 Fuel

Injection/Surging/Fixes”, and later my “Zero=Zero” effort on getting the Throttle

Position Sensor (TPS) optimized for best performance. However, along the way

in doing this I learned that spark plug performance and selection can play an

important part in overall performance of the R259 Boxer.

Being a thrifty person (a nice way of saying “cheap”!), I have habitually looked

for aftermarket service item parts that meet or exceed OEM requirements but are

more readily available and less expensive. Wear items like brake pads, oil

filters, air filters, and spark plugs are open-discussion items for me and it wasn’t

long after my Dec ’95 purchase of a used ’94 R1100RS that I began the process

that had ended with the sale of my ’87 K75S.

I’d had good luck with Autolite 4153 plugs in my K and I was eager to avoid the

extravagant price of the OEM Bosch plugs of about $10 fame. So armed with my

Autolite and Champion spark plug catalogs, I cross-referenced to the point of the

best possible match: Autolite 3923 and Champion RC9YC plugs. But wait;

here’s the difference.

The ‘94-spec OEM Bosch plugs for the R1100RS are FR5DTC, a unique three

ground electrode setup that surrounds the center electrode from the side. The

Autolite 3923 and the equivalent Champion RC9YC plugs are standard single

ground electrode “over” the center electrode as many of us are familiar with.

Would these “standard” plugs work?

I took the dive, bought Autolite 3923s, set the gap to the BMW specification of

.031” or .8mm, and went for a ride. They worked great! I even noticed smoother

power characteristics and somewhat less surging, and this was in early ’96

before I began my above-mentioned Injection/TPS experiments in earnest. So

you see, I’ve been using non-OEM plugs in my oilhead since about March 1996

(about 28K miles) with TOTAL success.

By the way, BMW changed their own plug spec to a two-electrode variety in July

1996 under the auspices of the “Low Friction Throttle Cable” service bulletin

#2748 which was an attempt to solve the surging I was investigating at that time.

In so doing, BMW revised the specified plug to the two-electrode Bosch

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BMW R1100 Spezifikationen Seite 59