Octane, I was not implying that you did not understand ignition. If it came across that way I apologise.
Brian, I'm the one who apologize !
I'm sorry but I'm writing in a for-me-foreign language and sometimes
my choice of words are maybe not the best.
Please accept my apology if I somehow came of condescending, pompous or un-friendly.
That was certainly not my intention!
find someone with a manual advance/retard on their bike and try it.
You don't need a bike with manual advance/retard to do that.
Really you can do it with a bike with ATD.
When it's idling, the ATD has not yet come into play (bob-weights at 'rest'.)
and the timing is correctly set somewhere around 4-5 degrees BTDC. (yes it's
BEFORE TDC, at idle)
so the situation is the same as if the ATD wasn't there or you had a manual timing-thingy.
Now 'mis'-adjust the timing to an earlier/more-advanced position
and see what happens.
My guess is that (I may very well have gotten it wrong) some misunderstand stems
from the fact that using a manual set-up , you
can set the timing at, lets say,
at TDC (zero degrees before TDC), or even a few degrees
after TDC,
to make starting easier.
If that's the case; then after start, 'advancing' the timing will of cause make it run better
as you in fact adjust it into proper timing , (let's say 5 degrees before TDC) for idling/slow running.
regardng revs increasing at idle when timing is advanced, are probably correct.
Yep; that's my point about the possible misunderstanding above:
It really depends on what is meant by 'advanced':
in
relation to what ?
Of cause one can say it runs better with timing 'advanced' if it's in relation to, let's say 1 degree BTDC.
Then one couls say, the engine runs with 'advanced'
all the time, including at idle.(around 5 deg. BTDC)
...but increasing 'advance'
beyond the proper timing, will
not make it run faster at idle /or slower return to idle.
That's the problem with using the terms 'advanced' and 'retarded':
some people (I'm not refering to any of you) seriously think
that 'retarded' means anything
after TDC and 'advanced' means anything
before TDC.
I prefere to use the terms 'early' and 'late'
and at all times that's in relation to the piston travel UP TO TDC.