Colortuning a 550

Brought a brand new colortune.

Like some of guys here on the forum said, the thing arc really bad. Even straight out of box, I didn't do anything to it. However, I was prepared for this, from reading some of forums.

I screwed the stiff wire (that came with the kit) onto the plug and covered it permanently with three layers of shrink tubes, from the tip (leaving the threaded end for the spark cap bare) to the edge of the window. Also, I stuffed the area around the plug in cylinder with a strip of old bike tube. It helped, the arc disappeared.

Now, using the colortune and turning the pilot screw for idling. I did NOT see any difference in color. The ONLY difference was that with the screw closed, the flash in the window was far between or none at all. The more I opened/turned, the more rapid the flash became but still it was the same color, blue. The only time I see it turn yellow/orange is when I twist the throttle quickly. Shortly after that, it would turn blue again.

I ended up leaving the pilot screw at 4 turns (I know most of guys have it at 2.5-3 turns). Better to have it running rich than lean. I have a couple of holes in the exhaust so...

The question, is this normal to see the SAME color when tuning the pilot screw on a 550? I recall some of guys saying that they didn't see any change in color.

Thanks!

 

Yes it is normal. Normal for a clogged or dirty carb. I would run some Seafoam through the carbs and tune again later. Make sure the Seafoam is run out of the tank so only fuel is being used to colortune. I would also look for air leaks around the airbox boots or intakes.

 

Um... I just cleaned the carbs, the whole 9 yards with everything except the enrichment tube apart.

I also sprayed both ends, the airbox boots and intake with WD-40 and didn't see any difference in the rpm.

Oh well... At least the bike is running much better now.

 

by enrichment tubes do you mean emulsion tubes? The ones in the center with the 16 holes in it? Those most likely have a clogged hole or two causing this issue. They must be cleaned thoroughly.

 

No, not emulsion tubes. I'm talking about the long, thin brass tube that's pressed into the bottom part of the carb body. It has only one, tiny hole going up to the enrichment section.

I did clean each hole in all 4 emulsion tubes. I doubt I missed anything cleaning each carb. I made sure by taking apart every part that could come off, soak the whole carb body in a 1-gallon carb cleaner, then using air compression to blast stuff out of every hole and opening I could find.

I didn't turn the pilot screws all way out, because if I did, I would just unseat the spring and that's too much anyway.

 

ahhh, ok. That one is difficult to get anything into. You have to get a strand of wire and carefully push that up through there. I thought I had my carbs pretty clean and good to go too...But I was still having some issues. The sync gauges bounced quite a bit and I did get a little bit of a rough idle sometimes. Well, after pulling the pilot screws out I realized that the o-rings on 3 of the 4 were in pieces. Some had parts clogging the pilot passages coming from the jets. I blew them out with 60psi of compressed air and installed new o-rings. last night I fired it up. It starts without blipping the throttle anymore, and it idles glass smooth. Oh, and the sync gauges don't bounce near as much. So I'll give it a good ride tomorrow and start tweaking the mixture.

Just my experience with pilot screws. If you had another set of o-rings lying around (in case there is damage to yours), I would recommend checking that all those passages are clear, and your o-rings are in good shape.

 

Yeah, I ordered 4 carb rebuilding kits from Z1 Enterprise that include o-rings for the pilot needle screws and fuel drain screws. About $17 per kit (ouch, I know).

Also, I brought generic o-ring (comes in a set of various metric sizes) from Harbor Freight. I used those to replace 8 old rings on two aluminum fuel plugs between carb No. 1/3 and No. 2/4.

I squirt high pressure of air through the brass tube and felt the air coming out of enrichment section. I did the same with the idle mixture tube and everything else.

I even removed the butterfly valve from each carb and reconditioned the butterfly valve seals with a swipe of armor wipe. When installing the screws on the butterfly valve, be sure to use some kind of thread lock lube. At the factory, they punch a dent on the bottom of each screw to prevent it from becoming loose and fly into the engine cylinder. Once you screw it out, the screw and thread lose some of that grip and you need to replace it with thread lock lube.

Everything works just fine. Enrichment works when starting the bike for for the first time when riding that day.

It's just that when colortuning, the color of flame remains at blue.

I've been told that I should try colortune it with the YICS tool installed so that's what I am going to do later.

Thanks for your help.

If I find anything different the next time, I will post back here.