1980 Bad misfire and cannot colortune successfully

Ok, I have had this issue before and had 3 valves out of spec, I have gotten all valves in spec and am still having the same issue.

I fully warm up the bike, let it idle for 10 mins or so, it will idle fine around 1000 rpm, however it will not take throttle.

During colortuning I can turn all the way out and still not get orange flame, but then at random times I will get orange flame and turning in just a 1/4 turn will give me that nice blue.

During this process, maybe due to warming up more, I don't know, the bike got to the point it would take throttle and rev up and sounded pretty good. However if I held throttle at a certain position, say trying for 2000 rpms, it will rev there nice but cannot hold it, starts backfiring, etc and really fights itself trying to stay there.

Here is a video I took which I am hoping will help in some way, this is right after I had this cylinder tuned fairly well, just on the blue side of orange, well upon restarting it is deep orange now.
However as you can see, when giving throttle, during acceleration it is a nice blue and during deceleration it has a slight orange, but looks good.
Then about half way through you will see me hold throttle and it will blue while accelerating and then will get white and has some bad misfires, this seems to be happening on all cylinders.
YouTube Video


Anyway, I just finished cleaning the carbs again, 1 carb had a fine red silt in it, but the rest were fine, fuel levels all look good, just about at the height of the top of the bowl (when hooked to the bike) and they drop only slightly when throttling up and quickly recover even during the sputtering issues.
The bike has fresh oil and I cannot seem to find any vacuum leaks using the various methods.

I am welcome to all thoughts, thank you.

 

Based on the video it looks like that cylinder may be getting spark intermittently. It should be firing regularly, unless the mix is getting so rich (i say rich because the flame is more often orange) that it can't combust.

 

Interesting, yes the issues I have been having, on any other bike I would think were electrical, but I saw a post on this forum somewhere that 90% of electrical problems are carburetor related on this bike .

Anyway, without getting orange sometimes at idle and with the hot white I was thinking lean, but the plugs always look rich, even if I don't see the orange in the colortune, of course I just figured this was from warming up with 'choke' and never getting to really ride or throttle up or burn off after warm up.

I truly believe this issue you saw in the video could be seen on any of the cylinders, so its hard to believe it's cylinder or coil specific.

The bike does have some electrical issues, namely I need to replace the fuse box because the bus style main fuses never sits well and sometimes I need to reseat it to get the bike to have power to starter and neutral light, etc. I have seen it intermittently make contact during running and all of the dash lights get bright on and off (like it's taking away power regulation and getting too many volts for a while), but all looks good when the fuse is properly seated. Also the blinkers don't work, but only because I haven't taken the time to rip all the wiring apart.

Thank you for the thoughts. Anything else that would be helpful to see for more diagnosis?

 

When you cleaned the carbs did you REMOVE:

-the emulsion tubes to clean them inside and out, including all the tiny holes?

-the pilot mixture screws, and replace their tiny o-rings?

Did you accurately wet-set the float levels? It doesn't sound like it. http://www.xj4ever.com/setting%20fuel%20levels.pdf

But start off by rebuilding or replacing the fuse box. You already know you have issues there; and intermittent connectivity to the ignition system could cause all sorts of crazy issues.

Also, in the video, I see spark arcing from the body of the ColorTune plug to the head. When the spark arcs to ground on the head it won't fire the plug. You may want to wrap the ColorTune lead wire with a layer of electrical tape or slide a hunk of heavy heat-shrink tubing over it.

Honestly, I think you're dealing with two issues at the same time here.

One more question: is your intake or exhaust modified? Is the bike stock or are we dealing with pod filters and/or a modified exhaust?