Dual-Spark Lower Plugs Covered in Oil

[zustation]

Well I’ve searched and can’t find an answer, so here goes. Changed the secondary (lower) spark plugs on a dual-spark R1100S and was surprised to see the threads on both sides were completely oil covered upon removal.

This seems unusual to me – has anyone else had this happen with their lower plugs? I can’t think of a good reason why there would ever be that much oil sitting on these plugs, unless maybe the oil was significantly overfilled at some point? Any other ideas?

[turboflyer]

Well sounds like overfill could be a real possibility. Though I would suspect all plugs would be pretty oiled. If the valve guides are really worn then oil can and will settle on the lower portion of the cylinder wall which just so happens to be right where the lower plug is close to. Might try doing a leak down test to see if things are mechanically sound.

[moze229]

Originally Posted by zustation

Well I’ve searched and can’t find an answer, so here goes. Changed the secondary (lower) spark plugs on a dual-spark R1100S and was surprised to see the threads on both sides were completely oil covered upon removal.

This seems unusual to me – has anyone else had this happen with their lower plugs? I can’t think of a good reason why there would ever be that much oil sitting on these plugs, unless maybe the oil was significantly overfilled at some point? Any other ideas?

You didn't search hard enough. Just kidding.

I recently started a thread on another subject, and it kinda turned into a plug thread. I had the same exact concern. Take a look and see.

Performance questions - R1100S

In addition, I also read somewhere (can't remember) that this is common for these engines. The secondary plug doesn't work as hard as the primary so carbon tends to build a little more. Second, oil tends to pool down at the bottom where the secondary plugs are.

Now, before someone comes along and blasts me for the latter information being incorrect technical jumbo, let me inform you of a couple disclaimers...

- I'm not a mechanic, and do not fully understand the way that these engines work - or any engine for that matter
- This is quoted from memory. The quality of my memory is pretty good, but do not take this info written in stone
- I am freely admitting now that I know nothing about these engines other that what I've read

Just trying to protect myself I'm sure that one of the more seasoned people here would be happy to jump in and correct me.

Matt