Spark Plug Check

This is what the spark plugs look like with all four PILOT FUEL SCREWS just under 1/2 out from lightly seated.
Plug 3 appears somewhat lean next to the others, and I'm wondering how to compensate other than adjusting that PILOT SCREW further out to enrich the mixture. For some reason the #3 cylinder always shows leaner than the others.

The Mikuni manual for the RS carbs specify the adjustment for the screws to be 1/2 turn out MAXIMUM! My adjustments stay within the specified range, but wonder how critical it really is.

Don't look lean to me in fact they look like they're cleaning up.
Steve

SWest wrote: Don't look lean to me in fact they look like they're cleaning up.
Steve

Looks like the electrode on 3 indicates a leaner burn and the base ring has a spattered-black appearance, when compared with the other plugs. Ideal would have them all the same...

How do I make #3 consistent with the others?

Questions Dave

How long have these plugs been in the motor ?
What kind of riding have they been doing ( RPM range / Idle time ) ??
All the plugs look too dark is my first impression but need more information .
Maybe not fatten up number 3 , but lighten up the other plugs .
Have you taken any new plugs and done a plug power chop to get a reading at WOT ?
Just fuel for thought
Dave

In my experience, a plug chop really only shows problems when things are pretty far out from where they should be. When everything is close to correct, the subtle differences take longer to show up. #3 does appear to be different, but it's difficult to say if it's the idle or part-throttle cruising that is causing it. It could be a tiny vacuum leak in the intake, or a sync issue. The mixture often gets leaner coming off of idle so if #3 is slightly more open, it could be slightly leaner.

Plugs can look like that and the bike can still run perfectly fine. They certainly don't look way off. #3 just looks a tad leaner in at least one throttle position.

Last year I had the peanut butter color I was looking for. Instead of just riding it I kept trying to get the color on the whole plug. I should have left it. It might have happened on it's own if I did. Now that I have higher compression, I'm starting all over again. As I've said before and was told, put at least 100 miles on it before making any more changes.
I like this guy.
"Before you start the tuning process, go to a quiet room, assume the Lotus Asana, stare
into a candle till your eyes cross, and chant this mantra: "The Hard Boundary is illusion,
everything feeds everything else!" Continue until you achieve Enlightenment--the
realization that everything you change in your carbies will alter something else, so that
you fully expect the tuning process to lead you in tightening circles instead of straight
lines (ain't that why they call 'em "circuits?") Richening the midrange by lifting the
needles may force you to go a step leaner on the pilot jets; richening the mains may
force you to drop the needles. Anticipate it; you'll be swapping brass quite a few times,
and that's as it should be"
www.amckayltd.com/vm34-36.pdf
Steve

I was doing some searching on the Gunson colortune the other day and saw that about 3 years ago you were really happy with results from it..... have you considered trying it with the new carbs. I see you said all the screws were at diff settings after you were done and it made a big diff.

I still have mine in the box and am thinking of giving it a try to get the air screws a little closer as I have a hell of a time hearing the diff in engine speed trying to adjust them.

I found the color tune will get you close but when I got the bluest setting the mixture was way off and the bike wouldn't run for SHT. I have better luck running it at 3500-4000 and listening for a miss then dialing it out.
Steve

I'm having to add engine oil more often than I would like. Perhaps that contributes to the black on the spark plugs...
which is dry with no oiliness at all.

Leaning the fuel mix produces popping on deceleration, harder starting, and an idle less-smooth. As is, she runs better than ever!
Much riding is 1/4 throttle or less, except most of the time when getting it on. :evil: .................

She cruises 80-85 no-sweat, and likes spinning more around the red line than less...which may partly explain the oil situation.

If you lean it out too much it will start using oil. I'd ride it as is and see if the color gets better.
Steve

SWest wrote: If you lean it out too much it will start using oil. I'd ride it as is and see if the color gets better.
Steve

This engine's diet has been consistently rich since the top-end was redone in 2015. This is the third season I've rode it like I meant it, with very little babying time involved.
Ok, I prefer to fly between stops, which I surely would not do that if the engine didn't like it. Besides, what fun is red line if you don't play with it. :whistle:

With that in mind, what is the average life expectancy in miles for a set of J-motor Kawasaki oem piston rings?

Using the power is good for the soul. The rings will last longer if it runs like it is supposed to. Not too rich or lean.
Steve