Initial electronic ignition timing on a B50.

[Kajay]

Hi Folk,
Advice please. At what position, crank rotation, do you use to initially set the rotor and back plate when installing an electronic ignition. My concern is dynamically the system should advance the spark to 34 degree BTDC once running past 2000rpm. So to set up statically should I retard the crank by the amount the system advances to set the static rotor position. That is if the system advances by 14 degree do I need to fix the rotor and back plate to fire at (34 - 14 degrees) 20 degree BTDC statically ( to get the thing running) ? 20 degree BTDC still seems a bit advanced for static time (I am open to correction on this point). Setting it any further retarded means the 14 degree advance the system makes wont get to the required 34 degree full advance required. (unless this can be made up by the allowed rotation of the pick up coil plates once running and being timed dynamically). The system that came with the bike is a "Sparx" (no instructions) and I can only see Triumph applications on their wed site where they show the system to give a 14 degree advance curve.
I am tempted to set if at a guestimated static position, hope I can get it started and then time it dynamically !
any help appreciated!
Ken     

[Bees]

What brand of electronic ignition have you got?


I used the Wassell one on my Starfire. From memory you set the engine to the 'normal' position btdc as per the workshop manual. So you'll need a timing disc and ideally the bolt that locks the crank in position.

Once your happy with that you put the rotor from the kit on the taper where the points cam normally sits. Then the stator goes on like the points backing plate usually goes. Perfectly in the middle as you may need to move it a smidge  when you strobe it.

You then need to line up some timing marks on the rotor and stator. ( on mine there was a thin line on each that joined up when bob on).

Then start the engine and stobe it as per guide so it's perfect. Make sure it's all tight and you'll probably never touch it again.

The system automatically advances with engine speed just like the weighted bobs do. But being electronic its way more accurate and of course no moving parts so nothing to wear.

Had mine for 4 years now. Starts 1st 2nd kick hot or cold. Never touched it since the day i fitted it. Its a dream.

[Kajay]

Hi Bees,
Thanks for the reply, the system is a Sparx one. It was on the bike so guess it worked at some time???
The BSA B50 workshop manual doesn't give a "static" timing figure or referee to one. It only talks about the dynamic figure and manually turning the original points cam by hand fully forward to set points opening point as a method of static timing to get the thing started. Then set up dynamically with strobe.
Wondering now what it says in the B44 manual !  I'm off for a look!
Thanks
Ken

[JulianS]

The norm with electronic igition is that you time it in the full advance position.

The unit should set to its pre programed retarded setting when you switch the power on and then advance as revs increase in line with programing.

[Kajay]

Hi JulianS,
That's great thanks, makes things a lot more straightforward !