There I was looking through some Lucas information on distributors (C10/C11) and the combined contact and adv-retard mechanism (C11G-C12ohv). I noticed the advance angle for the distributor versions is 9 to 11 degrees, yet the C11G/C12 ohv unit is 11 to 13 degrees. So the question is would making the distributor version go to 13 degrees make any difference?

I would guess that the advance retard mechanisms are likely to be so well worn out by now that neither would be near the original spec.

Most of us (I should imagine) set ignition at fully advanced so it's only going to affect the retarded timing (who really cares about that)?

Personally. I just wind my dizzy backwards and forwards until I get it to run how I like it and don't really have a clue what that might be.

As has been said, Couple of degrees here and there isn't going to make much difference on such an engine.

No harm in trying though.

I set all my bikes at full advance, at the manufacturers' recommendation where possible, and then tinker with it to a better running position. This will be as advanced as possible to avoid pinking.

Ray

To be fair and as I said, I couldn't tell you what ignition timing I have but where Ray and I may differ is. I like mine to chugg up a hill or round a corner at low revs so set mine so that it doesn't get "snatchy". That position is in there, somewhere, and it can take a bit of roadside fiddling to find it but eventually I'm more or less happy.

Either approach seems right to me though.

I assume that with rising octane levels in the 50s a slight advance of timing was a logical step.