Gunson Colortune, and the C5

[C5Performance]

slabghost » Sat Jan 10, 2015 12:15 pm[/url]":2lf3insh]
C5 is programmed advanced tied to rpm. There is no outside mechanical advance either weights or vacuum. Three sparks spaced at every cycle effectively burns all of the fuel charge. This leaves plugs very clean. Changing the heat range of the plugs is an interesting idea. I rather doubt there will be any noticeable change though.

I have mentioned this before but probably not for a long time.

If your engine was jetted properly with a stock ignition, then changing your ignition will not cause it to be "lean". Your fuel mixture entering the engine is controlled by the carb, never by your coils.

The brown or tan color on a sparkplug is residue. If you increase the efficiency of the burn, it makes perfect sense that your sparkplug color would be lighter in color (in our case sometimes no color at all). DO NOT use lack of color to justify a theory of lean jetting.
A/F meters should be used to verify correct jetting.

We recommend using one heat range cooler sparkplug with our ignition, and if needed, sometimes two heat ranges (NGK has very small steps in heat ranges so you can make reasonable changes).

Why run a cooler plug? Because you want the tip of the sparkplug to remain between 930-1472 degrees F (500-800 C).
If you burn more fuel with the C5 then a slight reduction in heat ranges might be needed to maintain proper plug operating temperature.

Plug too hot = glazing of the tip and detonation
Plug too cool=carbon deposits and plug fouling

Inspect your plugs for signs of overheating or fouling. I have never seen a dark plug after installing a C5 unless we jetted much richer afterward. On several of my personal bikes I kept the stock heat range with no signs of over heating. It's up to you to inspect.

One more important note: If you are jetting richer for performance, do not move up in jet sizes to the point where your plugs are dark again. If your engine is tuned for so much fuel that 3 sparks can't burn it all, you have gone too far! Our ignition can burn incredible amounts of fuel but excessively rich mixture is not what you should aim for as a goal.

If you are chasing mileage I would leave stock jetting.
If you are chasing performance I would jet richer as needed to maintain a 12:1 ratio (slightly richer than "perfect")

Sorry to ramble...so much to share!

 

[mcgovern61]

the sparkplug to remain between 930-1472 degrees F (500-800 C)

I tested my plugs and I can't really feel the difference in the heat range like I thought I would? (Matter of fact, I really can't even feel the tips of my fingers anymore now!) I guess I will have to let go of the plugs and put my them back in and hope for the best? :smilie_happy: :smilie_happy:

 

[joedrum]

sheesh gerry...that was funny ... but paul what a great post .....it brings to light that a better ignition system will widen the burn margins and also plug results to a small degree ...one thing ive learn is a carb system has to be divided enough to keep gas charge from getting out of margins to ...so power though rpm range can be a qeick as possible ... on my bike with the weber set up ...this seems to be more towards rich than lean in plug color ... if i go for better color on plugs and can get it ..like clock work will introduce some lean popping in various spots through rpm range ...to eliminate all that and get great excution through rpm zone color is dark brown and for my bike it is its color for for plugs ...for the plugs i am using might do plug change in heat range to check it out ... :thanks: