Why everyone needs a colortune plug!

So I tried out my colortune today. Only way it could be easier is if it turned the mixture screw for you. It was so much fun I had to play with it.

Something I noticed: You can see the spark. Plus, I leaned out a cylinder to where it wasn't firing. Spark clearly visible. So, this will also help diagnose whether spark is a problem.

I've had an annoying lope at idle. I was able to see with the colortune plug that #4 is missing intermittently all the way from very rich to very lean. I suspect I have a wire/coil issue. Of course I was pressed for time and it didn't occur to me to observe the spark until after I cleaned up.

Next session I will look for that spark. If it's not there in goes the replacement coil.

THANKS CHACAL!

 

I'm glad to hear of your success with the colortune as mine showed up from Chacal just this morning. I haven't had a chance to use it as my motor is still being rebuilt but look forward to trying it out as well.

By the way, to anyone who is thinking of buying it. I would highly recommend getting the caseas well, or arranging for something else to store it in. I had never really thought about the multiple parts, and didn't order the case. I sort of wish I had, just for future safety of the kit.

Thanks again for the order Len, it got here quickly other than a delay in customs that no one could control.

Best Regards
XJ750GUY

 

Put it in the snowblower.

 

LOL! My snowblower is a 1998 GMC 1/2 ton, popped into 4 wheel drive, and driven back and forth all over the driveway. But maybe if I tune up the neighbors snowblower he'll help me save my transmission! LOL

 

My brother bought one last year and I plan on using it this spring, what am I adjusting again? Is the only adjustment on my 750 seca is the pilot, correct?

 

The Colourtune plug is just for setting your idle mixture. Oh - and it's excellent to see if a cylinder is missing due to other ignition issues.
Anything off-idle requires needle and/or jet changes.

 

You can't load the engine on a Dyno and use it to tune? Or is it at cruise speeds the adjustments need to be made in the carbs?

I've never heard of this before, and it's a great project! I was looking to get it but i don't really NEED to set my IDLE levels, it's the cruise levels and full throttle levels i'm worried about.

 

Can you show a picture of the colortune?

 

I just used mine today for the first time. It was pretty fun and it runs great now. I got a NOS older one and I don't know if the newer ones are the same, but the plastic on the viewer tube on mine sure wanted to melt from the heat of the engine.

 

http://www.gadgetjq.com/ctune.htm
is a great over-view with pictures from included lit.

http://youtube.com/watch?v=NpZ5EW_Kupw

shows it 'kind-of' in action, there are two other colortune vids on youtube, maybe more, but the low quality video kinda makes things hard to see.

 

Nope - won't work. It's not a "real" sparkplug, so using it for tuning would be useless. If you tuned to a colourtune plug, then put in real plugs using the actual needle/jets (ie not idle) your tune will be all out of whack.

Best tuning is to do speed runs and a "plug chop" - kill the engine at WOT (wide open throttle). Feel for flat spots or hesitation while you're accelerating, then check the plugs condition for the real story of how the carbs are working.

 

My findings using the ColorTune Plug are that the Tool is invaluable for setting the Pilot Air~Fuel Mixture.

You see what you are doing to each hole as you tune for Pilot Mixture.

After considerable amount of tuning on a half-dozen Bikes ... I suggest using this technique when it comes to Colortuning the Bike.

Start-off Lean ... 2.5 Turns Out
Adjust the Mixture Screw OUT watching the Combustion through the Plug.
As you bring-out the Screw ... the Mixture will become BLUE.
Continue PAST and through the INITIAL Blue and deliberately run the hole RICH until it's too RICH and misses.

Bring the Screw back IN watching the Combustion Mixture for the tell-tale BLUE.
As soon as the BLUE "Returns" ... Stop there!

At this point ... the Cylinder is tuned >> "On the Rich Side" <<
This is good!

Get all four Dialed-In at that adjustment.

From that Point ... do your Fine Tuning by doing PLUG READS over time.

That point is a Healthy Rich.
Smooth running and ultra smooth Engine "Coasting"

Moving the Screw IN (Down) ONLY a DEGREE or two ... (Within the width of a Nickel) ... will put you "In the Blue -- On the LEAN Side!

Lean side tuning is Performance Tuning.
Aggressive acceleration, crisp, quick ... fast!
Pronounced Engine Braking:
Close the Throttles and you slow-down fast.

Continued PLUG READS will allow you to Adjust the Mixture to balance the Burn Color of each plug ... Individually ... a degree or two at the most.

IN!
Dialed-IN
Tuned-UP and ready for a long ride or a street fight ... you pick it!

 

>>www.gadgetjq.com/ctune.htm
is a great over-view with pictures from included lit.<<


turbobike, its interesting that you would post a link to Gadget's fixit page. When I had my Vulcan Drifter I used his site a lot.

 

One thing I noticed. As I got the mixture on a carb dialed in the idle would creep up. Then after I turned the idle down I'd swing rich. I suspect when I go back through I'll find the ones I did first will be a bit on the rich side.

 

Take a good look at the top of this 'T' ...

That's just about the width of the range between Lean and Rich when you finally get your Pilot Mixture Screws exactly where they need to be.

Throw-out what you learned about "Fractions" ... a quarter or a half a turn.

A quarter of a turn on a Pilot Mixture Screw can place the Mixture so far off that you will either be stalling-out and missing or flooding-it and fouling a Plug.
The Pilot Mixture Screws are THAT precise in their settings.
That's WHY they have ultra-fine threads.
Because they are going to need to be adjusted with precision.

The Colortune Plug provides the visual element to that precision.
You don't have a ballpark setting after you Colortune.
You are situated right in the infield ... a good place to be ... across the board.

Once you get the Bike Colortuned ... your IDLE will be nice and steady.
You'll have the Mixtures within a few degrees of perfection.

Those final few degrees of needing to be leaned-out or having some Richness added you will be able to do by inspecting your Plugs and actually determining how close the Mixture IS to HOW you want the Mixture SET.

You'll be at the point where a slight adjustment will cause the Burned Exhaust coloring your Plug tips ceramic end will be darker or lighter depending on what you do within the WINDOW of fine tuning.

Dark Brown -- Brown -- Light Brown -- Tan -- Sunburned -- Clean
____X_________X_________X________X_______X_____X__

<<-----------------------Within 3 Degrees--------------------------->>

 

I just googled it....

 

Yep...that's the difference between the older versions of the plug that you see on Bay for low prices versus the current versions. Gunson updated the material used to form the "almost clear" view window on the plug recently, which is also why there is no longer an "automotive" and "motorcycle" version of the plug (they're one and the same now).

 

While on the subject, does one colortune with, or without, the YICS ports blocked off?

 

I have done Colortuning BOTH ways. With and without the YICS Passage blocked.
If you are doing an initial Set-up, then you should leave the YICS Tool IN and adjust the Mixtures for Idle with the YICS Passage blocked-off.

After the initial set-up, it shouldn't matter if the YICS Tool is IN or OUT. You are adjusting the Carbs for IDLE. The Butterflys are supposed to be Closed for the Idle adjustment. The YICS Chamber is on the Cold Air side of the Butterflys. If they are closed when you are adjusting the Mixture with the Butterflys closed the YICS Chamber has little effect on the Mixture, anyway.

But, immediately upon opening the Throttles, the YICS Balancing does come into play and you will see and hear the effect of the system on performance.

With that in mind; Fine Tuning of the Pilot Air-Fuel Mixture with the Throttles Closed will provide an equally as accurate adjustment of the Pilot Air-Fuel Jet with or without the Tool.

The rationale being the Bike is expected to Idle (900~1050 rpm's) without the Throttles being opened.

Therefore the Mixture can be adjusted accurately without the YICS Tool.

The YICS Tool is necessary for Synchronization of the Carbs.
Once they are Sychronized and the Idle Adjustment Rod backed-off to place the bike within the parameters of TRUE Idle (Without additional Fuel and Air supplied from the Main Jets supplying Fuel because the Butterflys are opened drawing Fuel from the Main Jet Supply) the Idle Mixture is only reliant on the Air and Fuel from the Pilot Jets alone.

This means you will be tuning the Bike as you expect it to operate without the Tool.
I have found it to be quite precise doing Touch-up adjusting without the Tool inserted.

But, this Touch-up setting of the Mixtures are AFTER the initial go-through done with the Tool in place.

Since the Idle will normally RISE when the Tool is removed and the YICS Passage balancing the Air Flow after Sync ... performing the secondary Mixture settings with the Tool removed will allow you to get the Bike running the way its going too without have the Tool in there.

The resulting adjustment to the Mixture Screws is just a degree or two and will determine the Fine Tuning of the Engine for Performance Tune or Cruising Tune.

The tuning isn't done until the Bike Idles steadily, on its own, and the Mixture set to sustain the Engine from stalling when the Throttles are opened and the additional AIR brought in has sufficient volume of Fuel supplied by the Pilot Screws to smoothly accelerate without:

a) too much Fuel ... bogging-out the Engine as it waits for the Air from Intake and Main Air Jets ... or,

b) not enough Fuel to get the bike into the bottom of the power curve before the Main Jet Supply kicks in.

 

Rick,
Could we save this topic in the technical write up section of the forum.
You have given a very good explaination on the colortune plug and it would be easier to find it for future reference.

my 2 cents

Art

 

I second that! Good stuff Rick!!