There is a kit available that you use to adjust the fuel to air mixture of your carbs so they're providing EXACTLY the proper fuel to air ratio to the engine. I don't know what the kit is called or where it can be purchased, but I know one of the pieces of this kit screws into the spark plug hole and it has a looking glass so you can see the color of the combustion flame. You adjust the mixture screw(s) on the crads to attain a certain flame color, which indicates a perfect fuel to air ratio. Do any of you know what this kit is called and where it can be purchased? Thanks.

 

It is called a Colortune Spark Plug manufactured by Gunson's in the UK. (maybe spelt Colourtune, can't remember). Get on the net and type the name in for some web info.

I have had one for 15 years and they are a great addittion to the tool box. Very simple to use, and very accurate. An eighth turn on the mixture screw will show up easily. Basically, the colour of your combustion flame will vary depending on mixture, and this tool allows you to see the flame as you adjust the carbs. Yellow is rich and bunson blue is perfect. Start off yellow and adjust mixture uintil it JUST goes bunson blue and you're done. Full instructions provided and are easy to follow.

Be aware they cannot be used under load, so are suitable for adjusting mixtures at idle only, and do not work on two strokes unfortunately.

if you need any more info just ask.

 

Don't motorcycle carbs have a high speed mixture adjustment screw as well as a low speed? How does adjusting only the idle mixture screw aid in getting the mixture at the proper ratio at throttle settings other than at idle?

 

I haven't worked on my shawk carbs yet but all the other ones I have worked on have only had 1 mixture adjustment. Jet size and needle tapers/shims help regulate the high speed mixture.

Rick B
02 SH

 

I did some reading about the colortune and it looks like it can be used up to 4000 RPM. I knew a guy a few years ago who used one on his Yamaha Venture and he said it made a noticeable difference in how well his bike ran. Well worth the $60 asking price. Also, considering how poor the fuel economy is with the SH, it may help with that too.

 

This tool is useful for maintenance type tuning, it is not a substitute for time on a dyno selecting jet sizes and needle positions. Your carbs have a single mixture screw. Other jetting changes will mean changing jets and either tuning by feel if you are good enough, or using a dyno and a good operator.

 

Anyone else used one of these tools?

I'm ressurecting some old threads today... It's fun! This morning I read one about Hyperplates

James

 

I would love to play with a color tune as well - even if it really only helps you adjust your fuel screws and maybe pilot jets.


Tool nerd.

 

Lol. That i am