XJ Experts, Am I rich or lean

No gas in the crankcase, the YICS was blocked off when the head was off last year. Plugs were installed in the head passages, I was tired of messing with the YICS . Vac sync was done this spring.

 

How did you come to setting the mixture screws at 3/4 turn out?
Not knowing your answer, I would turn them out to 2.5 to 3.5 as a starting point.

The reading of the plugs is telling a story but maybe misinterpreted.

 

Maybe whatever you used to block the YICS is dissolving and is black when burnt off?

Or blocking the YICS threw the jetting way off?

 

Just kinda shooting from the hip here but those plugs show a "RICH" running conduction. IE two much fuel (or oil ) in the cylinders. this is probably caused by the carbs not being tuned. but if you got that taken care of it is time to be looking at valve seals. Also I live in Denver and my bike is jetted for sea level so my plugs look like that after a few months but there is nothing wrong. ( I will be fixing / rejetting that this winter when I do an complete over haul )

 

Look at the bright side.
Your not so Rich as to be Fouling the Plugs so that means you aren't too far from being where you want to be.

The answer to the initial question about the Pipes getting Blue, ...
Not with the Mixtures you're showing with those Plugs.
Them babies indicate you are running Rich and Cool. But not that far out.

Using the 1-Minute Stop~Watch analogy.
Where one full turn of the hand is 60-Seconds ...

Turn all 4 Screws IN 7 or 8 Seconds.
Take a ride where you get=on the Throttle HARD and return home.
Have a look at the Plugs and see how they look after a workout.

Keep track of how much of an adjustment you have made to each Screw.
Eventually, you will see and feel an improvement in the performance of the Bike as the Mixture gets made more Lean and the Combustion is made more powerful.

Let the Spark Plugs be your guide.
Once you have them looking the same color as a Brown Paper Lunch Bag , ...
enjoy riding the Bike you have Dialed-in for the rest of the Season.

Keep an eye on the Coloration of the Plugs, occasionally as well as any possible Oil Consumption issue as you Tune the Carbs more lean.
Make corrective adjustments to each Hole on an individual basis.

 

Something that maybe has been over-looked.
Fuel enrichment plungers.
Check that they are closing with lever in off position.
Should have free play between plunger top and fork lever when off.

Chasing an issue with indicators of both rich and lean can conjure up all sorts of WAGs.

 

Beside the very good advice allready given here, I always, when there´s a combination of "lean and black", come to think of this: (quote from response to "Frustration with low to midrange RPM & flowling plugs" off the XJ-owners mail list):

"(snip)
>When I check the plugs, they are a sooty black. I clean them and lean out
the fuel/air mixture screws (turning them clockwise). I have done this to
the point the engine starts to back-fire when decelerating using engine
backpressure. the plugs are still black.
(snip)

Peter Perry,-

Sooty plugs DOES NOT MEAN RICH MIXTURE. Sooty plugs means incomplete
combustion. There is a difference. Yes, rich mixture results in incomplete
combustion because there isn't enough oxygen to burn all the fuel. However,
LEAN CONDITIONS CAN ALSO LEAD TO INCOMPLETE COMBUSTION. (So can ignition
problems and mechanical problems.) If for some reason a cylinder does not
fire reliably on every stroke, then there is unburned fuel kicking around
inside the engine. When that cylinder finally does ignite, it ignites not
only the fuel introduced in that particular cycle, but also all the excess
fuel from all the previous unsuccessfull attempts at combustion. The
resulting effective mix can produce incomplete combustion. It is not at all
uncommon for a bike that is set too lean to produce black sooty plugs and
black sooty tail pipes. Often the acceleration hesitation you describe can
be cured in such a bike by simply applying a very light touch of "choke" to
enrich the mixture.

So, set your fuel levels at 3mm. Use your colourtune and after you set
things 1/2 way between rich (yellow flame) and lean (electric blue, possibly
misfiring, etc.) at idle (1,100 rpm or so) then give the throttle a quick
blip and hold at 3,000 - 4,000 rpm . The flame should immediately go yellow
as the rpms rise then fade back to Bunsen blue. If it does not, then open up
the pilot screw a bit so it will. This is the XJ equivalent of an automotive
accellerator pump -- the engine needs a shot of rich mix for maximum power
under accelleration.

Next, raise the rpm slowly and gently to 3-4000 rpm. The flame should remain
Bunsen blue throughout. If it does not then wind the screw in a touch. This
is the test of your cruise mixture setting."

- Haven´t read the whole thread, but have you tried colourtuning?

 

Problem Solved............... Dam PO
The pilot jets were the culprit. The jets had been modified by someone in the past. Even though the # on the side said 47.5 , the actual hole diameter was more like a # 60 jet. I replaced the pilot jets with another set of 47.5 and it runs perfect. I don't know where those jets came from but they are in the trash now. I don't know what made me compare the hole size in the jets I gues I just stumbled across it. I have a set of micro drill bits, sized .010 to .060 in .005 increments. I took some old pilots and started comparing the hole sizes. It turns out the jets had a much larger hole than they were suppose to have. I thought ...That explains it all.
The bike made a 250 mile trip on Saturday and preformed flawlessly. I pulled the plugs when we got home and they look great.

 

Wow ! Good job finding that.
Without proper sized jets to compare and stumble upon the visual size difference, you had to be inclined to actually measure.

I had thought about those jets, thinking they would cause this issue. But I also thought, well he has verified the size because he listed the size. I assume he knows the proper size. I too was depending on the size imprinted on the jet.