Sooty plug

[billywingnut]

Thanks for putting me right K2

[Greg65]

A picture is always good however knowing the theory and applying it is the dark art.

[K2-K6]

Thanks Greg65,  I was looking for a little schematic that I think administration has posted before to the same effect,  but couldn't find it.

Billywingnut,  I don't think it's such a black and while subject to be right or wrong, but open discussion I feel turns up some interesting detail that can be appreciated in trying to diagnose particular characteristics that someone is trying to correct. It's all good to offer a view for understanding/clarification as far as I'm concerned.

It shows from the carburettor design that this is an area that needs careful setting for differences in circumstances. They effectively fix the idle jet size for std engine setup,  but give adjustments of its effect by installing a screw to fine tune. If it were an absolute that screw wouldn't be there.

[mike the bike]

I'm reading this thread with great interest.  My plugs are always sooty, I was going to do the air screws today if it stops raining, because the figure I had in mind for the air screws was 1 3/4 turns out.  I don't know where I got that figure from though.  I was thinking only yesterday, at the traffic lights, tickover at 2000, this is why the japs fitted 2 throttle cables;  to make the revs die down a bit.  This variable tickover may or may not be related to the rich mixture, we shall see.