Correct Ignition Position

[Billington]

Since rebuilding the electronic on my 1932 BSA it likes to start and seems to run smoothest, when the ignition lever is in the retarded position.
I understand that running an engine in the retarded position can cause the exhaust valve to become too hot and burn out.
By just listening to the engine and riding it how would I know if I’ve set the ignition to retarded?

[Rex]

 Usually when they're retarded the tick-over slows right down, the exhaust takes on a more "doff-doff-doff" note and they don't want to rev cleanly but if you've never had the timing correct then I don't know that you would be able to make a valid comparison.
You are setting the timing at full advance aren't you?

[Billington]

Thank you for your reply Rex. I used the BSA Instruction Book for ignition setting, which is Piston at T.D.C Ignition fully retarded, Contact Breaker points open .003 inch.

When I have the ignition lever almost full rotated clock wise, (hence retarded) the bike pulls smoothly and strongly in all gears. It seems happiest  like this, but I'm wondering if this would result in the exhaust value turning black and being to hot.

[Bear640]

Like Rex said, I’d try it fully advanced.

[R]

Have you investigated which way the advance/retard lever actually works ?
My old Enfield is difficult to start unless the timing is retarded a bit, but when running it much prefers to be fully advanced.

Also, you mentioned 'electronic' - is this an electronic ignition system, not the magdyno or magneto ignition it would have had originally.
Some electronic ignitions have an advance built into them, such that the spark timing advances with revs.
You could then have two forms of advancing the spark timing, which would not generally be a good idea ?
 

[john.k]

Its usually pretty easy to tell where a low powered motor pulls best,and run with that advance.........I suspect you have probably set the timing well before TDC,and are getting plenty of advance..............a motor on full retard generally has no power ,and wont rev if you snap open the throttle................the biggest risk is excessive advance with high octane fuel.....no knocking,but enough extra load on the engine to break something.

[Rex]

Thank you for your reply Rex. I used the BSA Instruction Book for ignition setting, which is Piston at T.D.C Ignition fully retarded, Contact Breaker points open .003 inch.

If that's the case then clearly BSA expected the rider to set the timing lever in the optimum position when running. That being the case then maybe you're using it in the post-war way ie, just pull the lever around to the stop to set full advance, rather than just finding the best position when on the road?
Three thou seems very tight too?

[iansoady]

The .003" is probably just a timing setting value. It won't be the actual points gap. I'm assuming a magneto which would have a points gap of .012" or thereabouts although your use of the term "electronic" is a little confusing.

But normally it's best to time on full advance which is where the majority of the running is done. And I wouldn't necessarily agree that "the stop" will be full advance - different bikes have tight and slack wire advances, eg Nortons with the gear train timing gear had tight wire; when they reverted to each timing wheel driven direct from the crankshaft it became slack wire.

What model BSA is it? I'm sure there will be information somewhere about the correct fully advanced figure.

[Billington]

Thank you all for your replies. I’m going to try some of your ideas combined with the responses I’ve had from my “Stops When Hot” post.

[Rex]

But normally it's best to time on full advance which is where the majority of the running is done. And I wouldn't necessarily agree that "the stop" will be full advance - different bikes have tight and slack wire advances, eg Nortons with the gear train timing gear had tight wire; when they reverted to each timing wheel driven direct from the crankshaft it became slack wire.

This is true, and both my old Enfields have slack wire advance while the Scott has tight wire, but the slotted "stop" (in the travel of the points back plate or cam rim ring in the mag) determines the fully advanced to fully retarded range of travel, and for this purpose whether it's tight wire or slack wire adv isn't relevant. I'm assuming the OP has already sussed which way is advanced and retarded in the magneto.