Alright Hag...so THAT's what it looks like.Rook...send him yer plugs!

I'll measure , digitally, the wear across the gap and metallographically compare the deposits between #4 and #s 1-3 to determine any differences.

What I'm curious about is if the plugs had been changed out at the 7500 mile interval, would they show the same signs, just not to the degree, of 40k mile plugs. Number 4 appearing to have some oil issues?

The Gen 1 14 HAS oiling issues. It's usually #1 or #2 that lets go if that is going to happen. Oiling is better on the right. You'll notice that Romans' plugs he pictures in the OP on this thread show that one plug is dirtier than the other. I'll bet that was from #4, same as me. The gradual pattern of reduced oil deposits from right to left might indicate that my #4, 3 and 2 are getting oil and if enough is getting to 2 to seep up the spark plug threads, #1 is prolly getting enough. If there were other signs, I would be more concerned. No funny noises, 0 oil loss after changing the head cover gasket. This is not wet oil, it's not even damp. More like dry, slightly greasy carbon. This is not a profound leak of any kind.

Also, you have to remember this is over 40k miles on the same plugs. They're bound to have some shmootz on them. Like all routine maintenance, if it's done often enough, there probably won't be a lot of shmootz in in the engine unless there really is a severe problem.

I did not remove all plugs at the time but here is #4 at 11,000 miles. I'll venture a guess the same shmootz pattern would have been visible then, just less pronounced.

Rook I just changed a set out of a 2010 ZX14 with 32,000 kilo two days ago. I will post a pic for compare.

Rook I was asking more so because, in my head, I have some concern with reading these spark plugs... let me try to explain.

Kaws service interval is 7500 miles. Assuming this is for performance, is this the proper interval to also read spark plugs to try to determine combustion irregularities? We'll assume that for best performance, and reading the plugs, 7500 miles is the proper interval.

Now, on the flip side. If 7500 miles IS the proper interval to not only change spark plugs but read those spark plugs can you rely on plugs that were installed 40k+ miles and call it accurate? Or to say, although they worked fine they were in the engine too long and you are making comparisons based on what we expect them to look like at 7500 miles?

And then the flip flip side, many here feel 7500 changes is a complete waste of a good spark plug. But lets now assume it's also inadequate time to reliably read them unless the engines in horrible shape. Can I actually rely on reading my 7500 interval plugs to assess the engines overall health?

Rook I just changed a set out of a 2010 ZX14 with 32,000 kilo two days ago. I will post a pic for compare.

Thanks Romes. That's still less than half of the miles on these plugs but should be interesting. So far, I havn't seen a pic of a real clean plug come out of a 14.

Kaws service interval is 7500 miles. Assuming this is for performance, is this the proper interval to also read spark plugs to try to determine combustion irregularities? We'll assume that for best performance, and reading the plugs, 7500 miles is the proper interval.

Now, on the flip side. If 7500 miles IS the proper interval to not only change spark plugs but read those spark plugs can you rely on plugs that were installed 40k+ miles and call it accurate? Or to say, although they worked fine they were in the engine too long and you are making comparisons based on what we expect them to look like at 7500 miles?

And then the flip flip side, many here feel 7500 changes is a complete waste of a good spark plug. But lets now assume it's also inadequate time to reliably read them unless the engines in horrible shape. Can I actually rely on reading my 7500 interval plugs to assess the engines overall health?

My feeling is, plugs that have been left in 6x longer than suggested by the manufacturer SHOULD paint an exaggerated picture of what we normally consider signs of engine wear and/or AFR problems. Unless it's typical for plugs to come out perfectly clean at 7500 miles, I would expect there to be some schmutz on them by the time they get to 44000.

Whether it's 7500 or 11000 or 15000 that plugs REALLY should be changed because of electrode deterioration, these plugs were in so much longer than that, they're bound to exhibit a lot more signs of trouble. Given the relatively benign appearance of the worst one of the bunch at 11000 miles, zI'm inclined to believe the schmutz is a sign of spark plug overuse rather than engine wear...at least pending the results of my second compression test.

Ok cool, I intend pretty much sticking with the recommended/short interval changes. This year these plugs will have gone over, but then my riding goal was 7500 miles and I'm over 9k at the moment and don't really want to put knew plugs this short of the season left.

It's good to know I should be able to get a good read off Kaw's recommended interval.

Thanks!

Refering to the pic of my 44.5k mile spark plugs on the previous page, the plugs get progressively dirtier as they go from cyl #1,2,3,and 4. #4 is dirtiest. I noticed the same pattern of grease with my head cover bolts. The two bolts on the right are filthy the two on the left are pretty clean. This pattern might just be normal for this engine. I'm seeing pics of plugs and it looks like there is usually a progrssion of dirty to clean(er).