I have recently replaced my timing chain, so obviously had to retime the ignition. I set it at 3/4 btdc as stated in the Frank's Manuel. It starts easily, although now it has to be a lot more retarded than before or I get kick-back. The problem I am experiencing is that it runs in retard but the more you advance the ignition the worse it runs until eventually it cuts out unless you keep the revs up. It almost seems that the retard is the advance and the advance is the retard. I timed it on fully advanced as stated again in Frank's Manuel. Any ideas what I have done wrong? Many Thanks in advance.
Sounds to me like you timed it at 3/4" Atdc
.. that you've had the bike some time so are familiar with whether it's tight or slack wire advance?
3/4" sounds quite a lot - my rather later ES2 is specified at 5/8" and I'd be surprised if yours was much different.
Thanks Ian. It is definitely 3/4" btdc on mine.and its tight advance. Any more thoughts?
... setting it a little more retarded, maybe starting at my 5/8" figure? It does sound as if it's over advanced. I do believe we need to take original specs as a starting point rather than gospel as fuels are so different these days.
Modern petrol generally needs a bit less ignition advance than the traditional stuff. So don't go setting extra advance over standard...
Haycroft's Book of the Norton (owner's manual) gives 3/4" or 42deg for your year of ES2. But when you do the sums you'll find that 42deg equates to 1/2" BTDC. Could the 3/4" be a misprint? My '55 ES2 handbook states 5/8" and 47deg which tie up. The stroke of the piston did not vary over those years remaining at 100mm throughout.
I thought that ⅝" BTDC translates to 38 degrees with the 100mm stroke and the standard connecting rod which is 7.0 inches from the center line of the crank pin to the center line of the grudgeon (wrist) pin. I checked this graphically and ⅝" BTDC does correspond to 38 degrees. On some Norton publications the timing is listed as 38 degrees for the 100mm stroke engines. Be sure and check the magneto points setting at 0.012". I have some slop in my advance/retard lever that I have to accommodate. Best 'o luck. Geoff
The two attachments show Ignition Timing details for a number of Nortons. Both cover the period relevant to the age of the ES2 mentioned as well as other singles of that era.
Thank you all so much for your invaluable advice. I have reset at 5/8 and all seems well. Seems to be that the book figures of 3/4 is incorrect as resetting to 5/8 seems to make considerable difference. Very annoying to think the book should be correct, especially as its the original one for the year and then find its not. Makes you wonder what else is wrong. Regards to all.