Gunson Colortune

[brewsky]

Anybody have any experience with these?
Good or bad?
TIA
http://www.gunson.co.uk/item.aspx?cat=673&item=1853

[sotxbill]

Sorry, just cant resist.. what in the world is it and how the heck does it work... I'm intrequed.. Bill

[brewsky]

It is basically a clear glass spark plug which lets you see the combustion process as the motor is running.
You can then adjust fuel mixture by visually observing the resulting color of the exploding gas in the cylinder.
Like adjusting a Bunsen burner in science lab.
A perfect "Bunsen blue" color is supposed to be the perfect air-fuel ratio.
The advangage would be seeing results immediately, not having to pull plugs separately for idle, mid and wot throttle conditions, or trusting the calibration of air/fuel measuring devices.

[teazer]

I think I still have one that I bought about a thousand years ago. I never had much success but that doesn't mean that you won't.

Admittedly I haven't seen it for a while, so I may have tossed it out. If you want one cheap, I'll ask my son to see if he can find it.

[brewsky]

Teazer,
Welcome to the forum.
I would be interested if the plug is for 12mm holes.
Thanks.

[teazer]

Thanks

I'll ask my son to dig it out and then we'll both know.

[e3steve]

We had those in the UK decades ago; I first bought one to tune my old man's Austin A60 Cambridge with its (blindingly seemples) 1½" SU carb.

I never was able to try it out on my first CB77 or CA95 as it was the 14mm-thread version but used it, subsequently, on the ol' Speed Twin and BSA A7SS, neither of which ever seemed to need any adjustment and produced perfectly acceptable 'blue' combustion.

It disappeared years ago, eaten by the tool fairy, I s'pose; but I'd forgotten how useful it was. I think I may invest in a 12mm version, now that I know they're still available!

http://www.youtube.com/watch?v=6hFUvQ4gaPc