Spark Plug colours

[Terryb]

All,

Can anyone tell me how to rectify the fuel mixture between cylinders. The spark plugs on my Shooter have started to show dissimilar colours. Near side the colour is normal and the off side is showing heavy deposits of soot. Can the tappet clearances cause this?

[muskrat]

G'day Terry.
Different tappet clearances would barley be seen as different plug colours. More likely to be rings or intake valve guide. A7's don't suffer from induction bias as much as A10's, so if it isn't burning a bit of oil, that is the next culprit.
Another good test for a pair of colourtunes  http://www.halfords.com/motoring/garage-equipment/car-tools/gunson-colourtune-12mm-sparkplug-tuner
Cheers

[bsa-bill]

Colour tune's a good tool as well as mixture it show up  no spark

[Terryb]

Hi Guy's,

Thanks for the tip, I'll pop into Halfords and try the colour tester.

Went for a 140 mile ride yesterday, still showing soot on the right hand plug. Not burning oil and no black smoke from the exhaust showing. Performance seems to be unaffected.

[BSA_54A10]

If the plug is not firing all the time that can cause builds up of soot as well.
Howeer that usually gose hand in hand with a few pops in the exhaust

[a101960]

still showing soot on the right hand plug. Not burning oil and no black smoke from the exhaust showing. Performance seems to be unaffected.

I had a similar problem.  Tried all sorts of things including fitting anti bias gasket to eliminate it. What finally cured the problem in my case was removing the carb, thoroughly cleaning all the jets and passages with brake cleaner, followed by giving it a good clean in my ultra sonic tank. There was lots of crud in the idle circuit. Why was only one cylinder affected? I really don't know. You would be amazed at how much muck appeared in the ultra sonic tank fluid.
John