Thinking of purchasing a colortune for mixture screws

[ThrottleJunky]

The "by ear" thing is just not working for me. I can get both of my bikes close, but the changes in idle are so subtle with 4 cylinders that I just cannot perfect this "art" or whatever you would call it.

I think a colortune would help me greatly. My Morgan Carbtune works excellently for syncing, and I want a tool for tuning the mixture as well. Does anybody have one, and do you like it? Both my bikes were horribly out of whack when I bought them, neither even running.

"Bike A" has a small hiccup off idle. "Bike B" has an even smaller hiccup off idle. I just can't tell which cylinder, and how the mix is off.

[Bonz]

Not to over simplify things, however what about going 1/8-1/4 turn in or out on #1 cylinder, go for a ride and see how the off-idle stumble is. Better or worse? If worse, reset and go 1/8-1/4 the other way. If worse, it isn't that cylinder. Repeat, trial and error.

[Rasputin]

I have no luck with the by ear thing either. I purchased a color tune years ago and I love it. It is so easy to use and getting the same flame color on each cylinder is great.

[ThrottleJunky]

I have no luck with the by ear thing either. I purchased a color tune years ago and I love it. It is so easy to use and getting the same flame color on each cylinder is great.

Yeah, I talked myself into it and was all set to purchase one......only to find out they're not available ANYWHERE anymore.

[Geezer]

Yeah, I talked myself into it and was all set to purchase one......only to find out they're not available ANYWHERE anymore.

That's because they're not worth a crap... You're better off without one.

Tony

[IanDMacDonald]

Don't buy it. They're not worth the money in my opinion, waste of my money. What they're supposed to do, has no relevance to home each bike burns fuel. The XS does not burn fuel the same as other bikes, meaning the "Bunson blue" flame that the instructions call for, is not how the Yamaha runs happiest.

My advice is to use the "throttle chop method".

[Rasputin]

When I look up Morgan Carbtune, I see it is still offered. Took about 10 days to arrive and was very cheap shipping to Canada.
The statement "The XS does not burn fuel the same as other bikes, meaning the "Bunson blue" flame that the instructions call for, is not how the Yamaha runs happiest." is very true. The flame must be set slightly to the orange side of Bunson blue usually an 1/8 to a 1/4 turn.
Throttle chop works wonderfully after the colortune to double check everything but throttle chop does nothing for idling at all.

[ThrottleJunky]

When I look up Morgan Carbtune, I see it is still offered. Took about 10 days to arrive and was very cheap shipping to Canada.
The statement "The XS does not burn fuel the same as other bikes, meaning the "Bunson blue" flame that the instructions call for, is not how the Yamaha runs happiest." is very true. The flame must be set slightly to the orange side of Bunson blue usually an 1/8 to a 1/4 turn.
Throttle chop works wonderfully after the colortune to double check everything but throttle chop does nothing for idling at all.

Thanks for the insight. I don't care so much about the color per se, I just want a tool which allows me to set each cylinder the same, then I can fine tune it. As it is, I have absolutely no idea what's going on in each idle circuit. A throttle chop does nothing for me in that area. The bikes run excellently in the mid and higher throttle ranges, it's fine tuning the idle circuits where I am failing.

Curiously, Amazon showed 3 14mm Colortunes available this morning, so I ordered one and it's set to arrive Monday. I couldn't be more excited. In the meantime, my complete Yamaha o-ring sets for all carbs arrived this am, so I plan on taking one of the carbs apart again today for inspection. The choke is not operating correctly, as it won't stay open. I have to hold it.

[IanDMacDonald]

Just a fair warning . . . You could turn that mixture screw a full turn, and you're not going to see much of a difference in your color if you're using coils that don't provide a hot enough spark. Using OEM coils, vs. Dyna's is a significant difference with what you see using a Colourtune. I tried the Colourtune across a few different bikes (I ordered a few different threads), and was not happy with what I was seeing. Also, you have to let the engine cool prior to removing the Colourtune (it's plastic), or it'll break. So, that means you have to wait however long in-between each cylinder's adjustment. Also, if your mixture screws are not 100% up to par, i.e. (not broken tips), you will not see much of a difference in mixture color.

I did however buy a Carbmate Tec-Mate over the Winter, and love it over my Carbtune! A much easier way of syncing the carbs.

[ThrottleJunky]

Just a fair warning . . . You could turn that mixture screw a full turn, and you're not going to see much of a difference in your color if you're using coils that don't provide a hot enough spark. Using OEM coils, vs. Dyna's is a significant difference with what you see using a Colourtune. I tried the Colourtune across a few different bikes (I ordered a few different threads), and was not happy with what I was seeing. Also, you have to let the engine cool prior to removing the Colourtune (it's plastic), or it'll break. So, that means you have to wait however long in-between each cylinder's adjustment. Also, if your mixture screws are not 100% up to par, i.e. (not broken tips), you will not see much of a difference in mixture color.

I did however buy a Carbmate Tec-Mate over the Winter, and love it over my Carbtune! A much easier way of syncing the carbs.

Thanks for the warning on breaking it. My mixtures screw tips are fine. I've never cranked them down tight, and apparently the previous owners didn't either.

[Rasputin]

Ian is correct that hotter coils are nicer to work with. I have no trouble using mine with stock coils, you just have to pay more attention. I see differences within very small increments on the color on my bikes.
I only let mine cool enough to be able to handle them and move onto the next cylinder as I like to keep the heat as even as possible when adjusting carbs. I have never had an issue with them cracking.
If you run it rich for too long the glass will discolor bit and that makes the flame color harder to see and it can be hard or almost impossible to clean. That is my only gripe with the colortune.

[bikerphil]

I have closed up the gap of the Colortune plug to get it to work better. If you set the color to yellow/light orange at idle, it will probably be good.

[DiverRay]

Hook up a tach used for car tuning and use it! Adjust each carb looking at the RPM on the tach and adjust to the highest RPM, then go on to the next carb. If you can see, you can adjust it. You WILL need to adjust the idle RPM as you are doing this, as the idle should increase as you get closer to perfect.