Colortune Issues

Valves are in spec, floats adjusted and readjusted, new airbox to carb boots as well as new intake boot caps and fusion tape wrap. I propane tested the boots and carb and get no idle reaction. Carbs were perfectly synced last weekend and I've been putting around on the bike and overall it's not running too bad.

I got a 14mm colortune to finish it off and I cannot get the color to go orange. I have the mixture screws out to 4 turns, and even when adjusted out further it seems the colortune stays at blue. I can turn the screws in and the idle will drop and the bike will die, but cannot seem to get rich enough to get orange. Bike is stock besides the MAC 4 into 2 exhaust. Have a slight stutter around 5500rpms that's pissing me off and I cannot seem to take care of this.

Main jets were upped to 112s from the stock 110s, and I've got the idle set to 1000-1100 to run the colortune. When I blip the the throttle it still seems to want to stay bluish.

 

If I'm not mistaken, the color turns white when you close the pilot screws to a lean position, and orange/red when opened to a rich position. My experience has, been that there is a large blue range--on my bike from less than one to about 3 or more. I initially opened until I got the rich indication and then closed to get a good blue color. However, my plugs were still black and sooty. Over the next few weeks I slowly closed the pilot screws, about a dimes width each time, and the plugs got better and my mpg went up. Finally I went for broke and closed the pilot screws to a lean position--starting to turn white and the idle would drop-- and then opened them to get a blue flame and a smooth idle. I then installed new plugs and they look great, clean with a slight gray spot on the installation and a golden brown on the fire ring, or threaded part of the plug. So I am basically reading the plugs rather than depending on the colortune alone. If you follow my procedure you may need to read the plugs --new ones- and add richness a little at a time to get the right color plug. My bike is running better than ever.

I always see open 2 1/2 as a starting point on this forum. But my pilots are between 1 and 1 1/2. Interestingly, my Honda 750 manual says to set the pilots at 2 1/2 initially, start the engine and do a few adjustments and then set the pilot screws at a final setting of open 1/2!!

 

You've either got air leaks or not enough fuel.

Most likely causes are low float levels or carburetors not zestfully clean.

 

Since you already tested for leaks, I would suspect an obstructed pilot circuit or pilot air bleed jet not screwed in tight causing the lean condition.

 

My 700 has very large blue section as well
At 1/2 turn out I see orange
At 3 1/2 turns out I see white.
Everywhere in between is Dark Blue
So i screwed it back juuust before the dark blue at about 3 turns out
I'm also running larger jets, UNI air filter, and removed snorkle
Sounds normal to me.
Hey if the plugs read brown you're golden my friend
-Chris

PS I had the Mac 4-2 exhaust as well and I messed with it for about 8 months and couldnt get that stumble out. The Macs have no collector box... It messes with the backpressure on these CV carbs..
Ultimately made me sell my first XJ.....

 

You want the blue, not the orange. If it's blue, leave it. then keep an eye on plug color.

you've messed with the jetting and air supply, so all bets are off now.

The collector box balances the back pressure across all four tubes......same as a crossover pipe does.

dave

 

Something is not right here. 1/2 turn out is "almost closed" and should be white (= ultra-lean). 3-1/2 turns out should be orange (= rich).

 

I can get the mixture set so rich the bike will start missing and the carb "coughs" but the colortune still shows blue except when a miss and cough occurs.

 

Then it's time to pull the carbs and go through them again.... Something is not cleaned out

 

Still cannot get the bike to run correctly or the colortune to work properly.

-Valves are in spec
- plugs, wires and coils are all within a few months old and all test fine
- New carb to airbox boots and resealed the intake boots
- New aftermarket carb diaphragms
- Carbs were all vacuum synced
- New OEM air filter

I've gone over every inch of the carbs, boots and airbox with propane and cannot locate an air leak. I've taken the carbs off repeatedly and adjusted float levels within spec, while also cleaning and recleaning the carbs.

I cannot get the colortune to show orange no matter how rich I set the mixture screws. All four carbs are this way. I also have issues with the colortune arcing from the wire to the outer edges of the colortune plug, despite heavily wrapping with electrical tape; seems to work until the current finds its way through.

This is the second colortune I've bought and tried, but they just don't seem to work when I use them. Watched YouTube videos, read instructions, but cannot get good results.

 

Did you WET-set the float levels?

How "serviced" are the carbs? Mixture screw o-rings replaced?

Did you soak the rack? Break the rack? Replace the throttle shaft seals?

 

Floats are wet set. The carbs were as thoroughly cleaned as I could clean them without completely breaking them apart. I haven't replaced throttle shaft seals or mixture screw o-rings. Would either of those needing replaced cause all four carbs to runs too lean?

I guess I assumed the propane test on the carbs would highlight bad shaft seals.

 

I have just purchased a colortune kit and it's not here yet so I can't help you there but like bigfitz52 asked have you split the rack and did the fuel pipe o-rings and the throttle shaft v-seals?
I had always had some kind of issue with the performance of my bike until
I replaced all of the said seals.
After that and a sync my bike has never run better!

 

Inability to achieve rich typically means:

a) a massive vac (air) leak somewhere, either the throttle shaft seal, pod filters, missing O-rings in the mixture screw ports, reversed air jets

b) massive undersupply of fuel, fuel levels way too low, pilot fuel circuit clogged.

c) something else very uncommon (incorrect assembly of some key components), or a combo of the above.

Can you get the colortune to show rich (orange) by cracking the choke open a bit?

 

Even if I apply throttle I cannot get much orange at all. Would I be able to pick up air leaks at the throttle shaft seals with propane? I've gone over the carbs extensively with a propane torch and cannot find any leaks.

I built the pvc carb rack and adjusted my floats that's way. They all register 2-3 mm below the carb body using the clear plastic hose.

 

1. Check carbs for proper assembly + jet locations.
2. wet set your floats
3. check your throttle shaft seals, carb to airbox boots, and intake boots/caps.

Also, what was the reason for the increase in your main jets?

 

Main jets up to 112 because of MAC 4 into 2 exhaust

 

Revving the engine under no load will not give you an accurate indication of much, as the proportions of air/fuel don't change much.

Try bumping the choke on a 1/4-way or so, it's a completely different source of fuel than thru the pilot or main fuel circuits. If you can achieve orange in that manner, then it points to something clogged or amiss within the pilot fuel circuit.

 

This is your next troubleshooting step.

And bad throttle shaft seals will not always be detectable with a propane torch.

 

Leaning towards throttle shaft seals being the primary cause of my issue here, and I guarantee they're original. Choke on during the colortune did nothing to change the combustion color - still overtly blue.

 

This indicates that the choke system jets (located within the float bowls) are plugged up..............

 

ColorTuning is "Finding Idle Mixture"
The BLUE indicates you have "Found" the IDEAL Idle Mixture.
Colortuning saves hit and miss Idle settings by SHOWING you that you have the right FUEL~AIR Mix to IDLE.
Once you have the Plant idling, ... you must do some additional tuning to make the Plant respond to Throttle Adjustments.

You have to TUNE the Plant to respond to OFF IDLE.
The IDLE needs additional richness to support combustion when the Throttles are Opened.

In order for you to FIND --> Idle + Supplemental Richness for Accelerating and Off-Idle Performance, ...

You NEED to run "Hotter" Pilot Fuel Jets.
You need to Dial-in BLUE.
Then, ...
ADD more Pilot-supplied Richness to sustain combustion at the Instant the Plant transitions from a) Idle -- to -- b) Off Idle.

Blue is close.
Perfect for IDLE.
BLUE needs more Richness to get you Out-of-the-hole.

Adjusting the Pilot AIR Screw does NOT add FUEL.
Just MORE AIR.
The PILOT FUEL > JET < determines how much FUEL is supplied.

Once you have the PILOT >AIR< Screw "Out" to Max-flow, ...
Additional turns-out do NOTHING.
You have reached the Full Potential of the PILOT FUEL JET Supply.

Run hotter Pilot FUEL Jets.

 

I'm thinking Rick is right. New shaft seals, air/fuel mix screw o-rings and washers, as well as new fuel tube o-rings and the thing certainly seems to idle smoother, but color tuning still won't produce orange, no matter how rich I try to go. I can get blips of orange as I bring the mixture screws out, and the colortune will show a lighter blue the richer I set it, but no orange at idle. Even giving it a bit of throttle I can't really get much for orange.

With the MAC 4-2 exhaust the bike was upped to 112 jets from the stock 110s, otherwise it just has a basic air filter in the stock air box. Should I really need to go up another size for just an exhaust swap?