they look good. Don't change a thing. if anything your running a touch lean, but if it's EFI your good. I had to change mine to a colder plug. my stock ones were running hot.. they showed it. I always reccomend 1 colder than stock if you have any modifications. In my TPI L98 Corvette i went like 2 or 3 colder. car ran so much better. I had 50% less spark knocks on the scanner. If you look at today's performance engines like the LS1 and LS6 they run plugs much colder than the 80's. B/c of emission control systems of today allow us too. So if you have an older engine.. go colder in most situations. B/c they ran hotter plugs to burn up as much as possible in aiding reducing emissions. "I HATE THE 80's!" who's with me on that? Era of 100HP Z28's. Horrible time for cars.

Electrodes tend to wear on one spot from two primary things.

One is a substantial difference in electrical resistance. Not common with plugs like NGK, but quite common with things like Splitfires where one spot is noticably closer than others.

The second reason is swirl patterns in the combustion chamber. Some engines are very consistent in their swirls, as well as strong, and have the spark plug placed right in them. This is actually a good thing as the combustion process tends to be quite good in those engines. It results in a very specific and consistent wear pattern on the spark plugs.

It makes sense that I try a cooler plug givin' my propensity to engage in long climbs on a routine basis. Before stepping to spendy iridum I think I'll try getting the heat range correct b/4 dropping my precious cash.

What is your opinion of Denso's regular spark plug line-up card as compared to NGK? I'm curious, how many 'cooler' notches are you running with your motor?

Looks like you are keeping yourself busy there Wiretender. Plugs look good to me...I'd have to say your engine is running on the edge of optimum based on the plugs. I use NGKs and the NDs from Toyota in my 4Runner and the 4x4. Cant recall which has which at the moment but I see similar performance from both. Gapped at .032".

Glad the BVSV (Beavis) worked out for you. You'll have to take the time to come in more often and update us on your progress with the bike.

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

I just happen to find this article while thinking more about this thread... you do know your stuff, Thief!

How you can read spark plugs and select them


"So how can you tell whether you've chosen the right heat range? It's easy: a spark plug should be getting hot enough to keep its insulator nose completely clean, with all deposits burned away, but not so hot that its electrodes show signs of serious overheating. These are things to look for on a new plug that has been subjected to a few minutes of hard running. After many miles of service insulators acquire a coating of fuel deposits, with some coloration from oil in two-stroke applications, and there will be some erosion of the electrodes even when everything is normal. Don't try to read old spark plugs; even the experts find that difficult. New plugs present unmuddled information about what's happening inside an engine, and can give you a complete picture after just minutes of hard running. At least they will if they're running hot enough, and that should be hot enough to keep the insulator clean.

It's impossible to separate the question of ignition advance from the primary evidence of spark plug overheating, which is most strongly shown on the plug's center electrode. If you inspect this electrode's tip with a magnifying glass and see that its edges are being rounded by erosion, or melting, then you know there's overheating. You should also have a close look at the tip of the ground electrode, checking for the same symptoms. Finally, inspect the condition of the insulator, which should be white but with a surface texture about like it was when new; a porous, grainy appearance is evidence of overheating. If the signs of overheating are confined mostly to the center electrode you can bet you're using too much ignition advance. Retard the spark timing in small (two or three degrees) increments and as you get close to the optimum advance you'll find two things happening: first, the whole plug will be running colder; second, the center electrode will begin to acquire a film of fuel deposits extending out from the insulator nose toward its tip."

FWIW, I ran the new NGK's real hard that I had on hand. They look great so I'm going to stand pat and have another look 1k miles or so down the road. I do need to get after an exhaust modification so I think I'll tend to that next...

What part of UK are you from? Did Dad and Granddad work the Isle of Man TT events by chance?