Planning to do my valve check today... A new plug it is. BTW how close to clearances would it be OK for you guys to button back up without changing shims.
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On Sep 12, 2015, at 12:29 AM, "walk9940@... [DSN_KLR650]" DSN_KLR650@yahoogroups.com> wrote:
I have been reading through the spark plug discussion, and figured I have a few things to add. I started using Iridium electrode spark plugs back when I was riding 50cc two strokes 20 years ago. Iridium electrodes are an engineers dream because they are thin enough to focus the spark, yet resistant to erosion. Because of the fine electrode, iridium plugs also are extremely resistant to fouling. I have been able to use some weak ignitions (old Femsatronic) successfully because of this. The concentrated spark is also more efficient at igniting the fuel charge. This translates into more engine output and or better fuel economy. There are many dissertations out there that prove that iridium plugs are more than snake oil such as a split fire plugs etc. Iridium plugs are also OEM on most cars these days. In my experience, from my weed wacker to my car, Iridium plugs mean hassle free starting(ethanol bunged up carbs excepted).
While we are talking about fancy electrodes, it is worth noting that some coil pack engines will share a coil pack for 2 spark plugs. The result is that one plug will have the spark jump from the center electrode to the ground electrode, and the other will jump from the ground electrode to the center electrode. Looking at a set of worn plugs, you will see heavy erosion on the ground electrode of these plugs. This is where double platinum spark plugs are used. There needs to be a resistant surface on both the ground and center electrode. Double platinum plugs are not necessary in a single cylinder engine.
I prefer the NGK DPR8EIX-9 in my KLR. I buy them in a box of 4 for around $30. When I put the 685 kit in my KLR, I had a problem with the oil scraper ring spring. I bought the parts directly from Schnitz, and they were less than helpful at correcting the problem. Frustrated, I installed the spring anyway. ! At about the 4K mile mark of the Great Divide Ride, my KLR started burning oil. On the final ride home from NM to GA, the bike was using a half qt of 50w every 100 miles. When I tore the engine down, I could not believe that the plug was still firing. There was just a hole in the ash from the spark. My KLR never failed to start, which with that much oil going through the engine was a miracle to me.
When I do my valve adjustment, or when I am prepping for a big trip, I install a new plug. For a $7 dollar part, it is not worth chancing a problem. Leaving a spark plug in too long is also an invitation to remove the threads with the plug. Small problems can snow ball into all sorts of unintended consequences. Considering the hassle of removing the side covers, seat, tank, along with any obstructing luggage/farkles, it is cheap insurance to replace the spark plug in the comfort of my garage.Just my own .02. YMMV.Cheers, Doug