BSA Owners' Club Forum

The BSA Workshop => Singles => Topic started by: chrisgoodwin on 11 October, 2017, 15:48:11

Title: B31 Manual Advance/retard
Post by: chrisgoodwin on 11 October, 2017, 15:48:11
Hi All,
I wonder if anyone can help with this question.
I have a Lucas MO1 Magneto with the advance/retard cable housing on the left hand side (Looking from the drive end) Right hand side (When looking at the points)

I think that this is a tight wire advance set up and the timing should be set with the cable slack (Retarded) and the lever operated to advance the timing for normal riding.
Please see attached pic, not my mag, but lifted from a flea bay page.

I'd appreciate it if someone can confirm it is a tight wire advance.

Cheers
Chris
Title: Re: B31 Manual Advance/retard
Post by: JulianS on 11 October, 2017, 16:13:54
Timing is advanced when the face cam moves in the opposite direction to the rotation of the points.
Title: Re: B31 Manual Advance/retard
Post by: Greybeard on 11 October, 2017, 18:06:14
Hello, Chris.
Mine is a tight wire advance and the cable goes into the mag at the back side (of the bike, that is). Timing should be done with the ignition fully advanced. Haycraft (Pitman Book of the BSA) says maximum of 1/2 inch BTDC with premium fuel.
How's the project coming along?

Steve
Title: Re: B31 Manual Advance/retard
Post by: chrisgoodwin on 12 October, 2017, 12:34:12
As ever, thanks for the info, looks like mine is indeed a tight wire advance, could be a pain in the a%*e if the cable snaps!

Steve, it's going well, engine complete as are the oil lines, the mag is on the bench being 'looked at'. Forks are ready to go on and the plan is to have a rolling chassis next month

Cheers
Chris
Title: Re: B31 Manual Advance/retard
Post by: ANDY HIGHAM on 12 October, 2017, 14:47:49
How often do cables snap?
Most cable failures are either fraying through rust or incorrectly soldered nipples pulling off

I make my own cables using PTFE lined outer conduits. The inner wires are splayed before soldering and are soldered in a solder pot (about 15 off Ebay)
Most parts available here https://www.venhill.co.uk/