Colortune Review
The Colortune device is a spark plug that allows you to see the colour of the flame inside the combustion chamber (engine) when the petrol ignites.
All you have to do is look at the colour.
Yellow is rich, white is lean, deep blue is perfect (light blue is a little
lean).
It really is as simple as that.
Of course you want to see if the flame changes colour at
different throttle positions and engine revs, so you simply turn the throttle on
the bike.
This is done with the gearbox in neutral so the bike is not moving.
The Colortune device is very useful for finding and fixing
faults because it shows you immediately when it is fixed.
If you are a more advanced enthusiast / mechanic, it can help you get the
mixture correct when fitting non standard exhausts / air filters / carb or
engines.
The CG125 engine uses the 12 mm version of the Colortune (make
sure you obtain the 12 mm version).
12 mm is a very common size of spark plug used in motorcycles of all engine
sizes (including large engines).
So the chances are the Colortune will be with you for a long time and its even
more useful when working with engines that have more than one cylinder.
All NGK spark plugs that begin with D are 12 mm.
How To Use
1) Warm your bike up to normal temperature, remove your spark plug.
2) Use a dab of grease to hold the copper washer on the Colortune plug.
3) Gently tighten the Colortune plug hand tight just to make a snug seal (a 16
mm deep socket may help, do not use a ratchet).
4) Attach the extension and connect your HT lead (plug cap), make sure your plug
cap is out of the way (not touching anything).
5) Start your engine and look at the colour, adjust your
Idle Mixture Screw to
get correct colour.
(you may find you have to open the throttle very slightly or
turn up the Idle speed screw to
stop it from stalling)
6) Carbs fitted with accelerator pump - the idea is a yellow colour as throttle
is opened and then settles back to blue at a steady throttle opening.
This can be a bit fiddly to get right.
Caution
Do not over rev the engine by holding the
throttle fully open for to long (only go to full throttle for a fraction of a
second).
To prevent excessive heat build up in the Colortune and engine, you should not
use it continuously for more than 5 mins and avoid extended high rpm.
When you have finished with the Colortune, the plug will be hot so be careful.
Carburetion Basics
http://hondanighthawks.net/carb14.htm
Spark Plug Colour Chart
http://www.verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm
Some links I have found on the internet about the Colortune
User Manual (more complicated than it is in reality to use, but
also covers the advanced things for real enthusiasts / professionals).
http://www.gunson.co.uk/items/pdf/Products/G4074_Inst_Colortune_English.pdf
Videos
http://www.youtube.com/watch?v=dwRw_Fb8LWg&feature=related
http://www.youtube.com/watch?v=NpZ5EW_Kupw&feature=related
http://www.youtube.com/watch?v=5BU-5FhX_Qc&feature=related
http://www.youtube.com/watch?v=7fhLXsZ59Mc