Spark Plug Color Check

These spark plugs have a couple hundred miles on them since changing Pilot Fuel Jets from 22.5 to 25 in my RS34's.  I have 27.5 ordered to try with 1.0 Air Jets (one-step leaner), but she runs better than ever at this point, so that may just be a waste of effort.
I hooked up the Morgan Carb Tune Sync tool, and found 1 & 4 off a little.  After tweaking slide adjustments for at least a half hour, I seem to have discovered the illusive sweetest spot.  It ended up being a tedious-fussy process, since slightly-off wasn't going to cut it this time.  It takes only a slight mis-adjustment to throw the balance out of whack.

 

From what I know about reading plugs, your mixtures look good. I see your plug heat range is to hot. There should be a color change on the earth strap from grayish to dark just before the strap starts it’s bend. Your plugs show no color change at all. 

www.dragstuff.com/techarticles/how-to-read-plugs.html

Looks a touch lean to me.
Steve

Sometimes you can go nuts chasing what you think may be the "right" plug color.  Yours looks pretty good to me at face value, but the real test is how does it run.  You stated it "runs better than ever".  I would therefore leave it alone.  No sense fixing something that to you isn't broke.  I clean or change my plugs at 500 miles just because I can and it's cheap insurance.  Same for oil and filter.  I have had my KZ out twice this year and so far it is running like a top, knock on wood, I am not going to mess with anything right now.  I half expected something to go to pot after its winter time nap, but so far it's great.  Not going to mess with a thing out it right now and enjoy the ride.

Rick H.

Mikaw post=846196From what I know about reading plugs, your mixtures look good. I see your plug heat range is to hot. There should be a color change on the earth strap from grayish to dark just before the strap starts it’s bend. Your plugs show no color change at all. 

www.dragstuff.com/techarticles/how-to-read-plugs.html

THIS ...^^^^^^^^^
Base ring is mixture .Full turn of light soot is fine.
Earth strap is heat range and should be clean from the bend.
Clean down to the weld show a little hot so go colder on the plug.

Awesome responses!!!  

BTW, what is the Denso plug number for the next cooler plug of this type, and would richening the fuel mixture and/or changing the plug gap do the job? 
Spark plug gap is .78 mm.  FSM spec is .7 to .8 

The ignition is operating with Dynatek copper-core plug wires and NGK non-res caps.  The 2000 module set on #5

Another pic without the flash:

 

They still look on the hot side..
Denso IW27 is the next coolest ( NGK 9  equivalent) which is what i run in some of mine.

wrote:

They still look on the hot side..
Denso IW27 is the next coolest ( NGK 9  equivalent) which is what i run in some of mine.

 

Thanks again zed1015

I ran one tank of Mid-Grade E10 gasoline with the new plugs, which produced excessive carbon which was removed with a fine wire brush.  After that was Regular E10.
Denso IW27 spark plugs (bottom row) after 330 miles:

 

The IW27’s on regular gas Look like a sweet spot.

I have had bikes that the plug were sooty black at highway speeds, yet would start to clear up in just the short time it would take to get through the subdivision and into the driveway. I now do 3 plug chops.
1. start bike and let it warm up. Shut down and put in new plugs. Restart and let idle for 10 minutes. Do not use choke or throttle. Shut down and check plugs.
2. Gentle ride, 50mph, high gear, level road for 10 miles. Hit kill switch and pull in clutch at same time and coast to a stop. Check the plugs.
3. Highway at a constant 80mph for 10 miles. Hit kill switch and clutch, and coast into a rest area or exit and check plugs.
This procedure will tell you where you need to tinker.


 

Yep, gotta use new plugs and do chops.
Otherwise, you are looking at the entire history of that cylinder since you put the plug on.