XR7LDC- What is this spark plug?

[Ridealot]

The story,
In January I bought a '93 K1100LT that had just been serviced by BMW of Denver. The previous owner gave my all the service records. They have Bosch XR7LDC listed as the plug they installed. The stock plug is a XR5DC.
I looked in a Bosch spark plug catalog and I can't find the XR7LDC listed. I pulled one out of the bike and looked at it. It is a dual electrode plug.
Does anyone know anything about these plugs? Are they O.K. to run in a K11? They have been in the bike all summer for about 8k miles without a problem. I did notice that cylinder #3 is running leaner than the others. I don't think I ever noticed that on my old K100.
Any info on what the heck these plugs are for will be appreciated.
Tom
Salem Or.

[azgman]

The Bosch XR7LDC is also used in the K1200LT and is all but impossible to find. Many have switched to the Splitfire #TP416D with great success. (works great in my K1200LT)

[Ridealot]

Thanks for the info. At least now I know that it is a plug for the later K bikes.
I am also wondering if anyone has found a car parts store that has been willing to order the stock Bosch X5DC plugs?
I find it hard to believe that the local BMW shop wants just a few pennies less than $40 for 4 normal spark plugs. This just seems to be about four times what they should cost.
Has anyone found a reasonabley priced online site for buying plugs?

[deilenberger]

Originally posted by ride-a-lot

Thanks for the info. At least now I know that it is a plug for the later K bikes.
I am also wondering if anyone has found a car parts store that has been willing to order the stock Bosch X5DC plugs?
I find it hard to believe that the local BMW shop wants just a few pennies less than $40 for 4 normal spark plugs. This just seems to be about four times what they should cost.
Has anyone found a reasonabley priced online site for buying plugs?

The X5DC plug was used on a few BMW cars, such as the first M3 series (late '80's vintage) so it's not that hard to find. Usually costs about $3-4/per. Last a LONG time - if you keep an eye on the gap, good for 25,000 miles easily.

Best,

[azgman]

Here is the story on Bosch plugs...

[Ridealot]

Nice graph on the Bosch plugs. After looking at it I am going to change the plugs on my bike. The XR7LDC are two heat ranges to high for my bike. When I inspected them they all looked like they where on the lean side. Cylinder #3 was noticabley leaner than the others which looked the same.
I'm going to save that graph for future use.
Thanks
Tom Salem Or.