Colour tune

[a101960]

Has anyone had a recent experience of playing with a colour tune? I have just been playing about with mine and I can’t seem to get that nice Bunsen blue coloured flame. The bike starts and runs O.K. But power seems to be a bit down with the choke in the off position. On examining the spark plugs the colour looks alright (a sort of brown/grey colour). Maybe it is just the way modern petrol burns? I did notice that the plug gaps need closing up a bit would that make a difference? The carburettor is a 389 monobloc, pilot 25 main jet 420, and a 3 slide. I was wondering if going up to 30 pilot would be worthwhile.
John

[morris]

It's been a while since I got my colourtune out, but I remember that it's very difficult if not impossible to get a blue combustion flame on the pilot.
There's a nice blue flame though as soon as I open the throttle a bit, and it stays that way through the range, so I don't let it bother me to much.
After all, how much time are you on tickover when you're on the road?

[kiwipom]

hi guys, found this interesting post on the net.  A Few Random Tech Tips www.theflyingbanana.com
  might give it a go just for the hell of it, also other interesting tips,cheers

[muskrat]

I have the same problem getting a good colour on the pilot but rich is better than lean (to come onto the slide and needle quicker). It's hard to get it right up high on the bench (http://www.a7a10.net/forum/index.php?topic=10630.0) without load. You can get it to red line but still only be on 1/3 throttle. Maybe you could set up a GoPro looking at the colour tune while riding!
Cheers

[BSA_54A10]

Modern fuel, which is not petrol does not burn with the old rich blue colour that real petrol used to.
However too rich still burns yellow and too lean still burns white.
I use mine at least once a week on hand held engines.
It is just a matter of experience.
I do a lot of oxy welding so I am attuned to a neutral blue flame.
No where near as rich as Gunsons make out unless you use the long dark tube  which is difficult on a bike.

When working on a motorcycle I fill a 1 pint fuel tank, pinched off a push mower and then remove the bikes tank.
Hang the alternative tank from the roof , clothsline , fence  balcony, what ever.
When the tank is empty time to stop and let everything cool down.
Being a loya Aussie, I use a Victa tank because it has a shut off tap on it.