Electronic ignition and total advance

[IanMc]

Hello - I treated myself to a Enduralast electronic ignition recently.  I have a straightforward question on what is the standard maximum advance on a 1988 mono, ie. with the BMW electronic system/Hall sensor set up.  From my experience with this new system, it seems it is not 32 degrees as set out in the Haynes manual.  Can anyone confirm what it actually is?

Here's the back story. The Enduralast instructions are aimed at all airheads with a couple of exceptions.   The key point is the system maximum advance is set at 34 degrees which they reckon is the best for all models regardless of original set up, except for, of course, R65s and later Hall sensor models like mine!   In this case, they say go with/stick with the standard 32 degrees, but a whole side story on diameter of flywheels and distance between the timing marks.  I initially set it up as standard at full advance (Z), but I could not see the idle mark (S).  I expected this to be visible, but 2 degrees out, ie. about 3mm.  Start up from cold was definitely worse and lumpy, but rides fine once warmed up albeit the tickover is higher.  So, I am thinking it is too far advanced at tickover.  I then thought I'd try it the other way around by advancing the timing at full advance to 34 degrees and therefore reduce the advance at idle (3mm above the standard crankcase mark).  Definitely ran better at low speeds but I still could not see the S mark at tickover.  So, assuming the Enduralast system is definitely 34 degrees, then it follows that the standard maximum advance must be less than 32 degrees on my specific model.  See question above!   If it is, I think the Enduralast system must be faulty.

Thanks for any advice!

[Barry]

My understanding is that 34 deg is the maximum advance which makes it 2 deg more than stock. I don't think that's worth worrying about especially if it reaches maximum advance at higher revs than stock. So I would set it at an estimated 34 deg which would be a little over half a tooth past the stock timing mark.  If you still can't see the S mark at idle then something is wrong with the amount of advance that the unit is providing.  The amount of advance is switchable isn't it ?

As far as I know stock advance is 32 deg for your model but you could check by counting the number of teeth between the OT mark and the Z mark. I make it 3.24 deg per tooth.

[IanMc]

Thanks for your advice.  You've answered a side question about measuring distance between timing marks - hadn't thought of counting the teeth!  I think this is now resolved.  There is the 'main' universal curve then one for dual plugs and a hybrid one.  The hybrid one is 32 degrees with a slightly smoothed out advance curve.  On this setting With Z lined up at full advance, the S is at the top of the aperture, so a little bit advanced but pretty good.  The bike certainly starts and idles fine now so I'm leaving it at that!