Topic: Random ignition timing questions

[ntm1974]

Bike is a 76 cb750 with hondaman ignition.

After reading the FAQ on ignition timing, I had a questions a few questions.  I'm sorry if these are dumb questions:

1. If the spark advancer goes past the timing mark, what is the negative cosequence?  It seems like this would give possible advanced ignition and cause it to run hot: is this correct?

2. Do both points need to be set at the same dwell?  If so, what is the negative consequence of having them set at different dwell?

3. How do you adjust the advance timing marks without negatively affecting the idle timing mark? 

4. I've read about people cutting the spring down on the spark advancer and/or lightening the weights.  It seems like this would retard advance timing.  Is this a viable way to adjust the timing advance or does this have another purpose?

5. Is a longer dwell alway desireable for the best spark?

I know it's basic questions but thanks in advance for any replies.

[dave500]

random answer,with a timing light set it so it advances to the full advance mark,it must not exceed this,engine damage from pinging can result,as when climbing a steep hill or loading the engine,where it ends up at idle so be it so long as its not retarded behind the fire mark,both points should have the same dwell,the spark intensity will vary,longest dwell will saturate the coil better.

[Bodi]

Set the points gap to spec, and the dwell will be to spec (assuming the points cam isn't badly worn, keep some grease in those felt pads and ensure they touch the cam).
Set 1-4 first via the late rotation then set 2-3 via its sub-plate. Set to the advance mark at around 3000rpm. The idle "F" mark is not critical, the advance mark is. The engine will idle fine within a very wide margin of retard. A bit less advance at working RPM will rob you of a lot of power, too much advance will cause preignition or "pinging" which you can not hear or feel when riding (unlike in a car where it is noticeable) and this can (will?)  burn holes through your pistons. If you always use premium fuel you can set the advance timing a bit advanced for a tad more high end power.