classic motorcycle forum

Motorcycle Discussions => British Bikes => Topic started by: Andy_G on June 27, 2008, 04:52:25 PM

Title: BSA B33 Magneto setup
Post by: Andy_G on June 27, 2008, 04:52:25 PM

Hello all, I previously posted for info regarding an M20 but seems I was wrong, it's a B33, frame No XB3111298, engine No XB331259. We're unsure of the make of the mag dyno but we think it's lucas and the number is E3HM. The bike kicks back but fires up eventually, popping and back-firing. I'm sure the mag is set up wrongly but having had no previous experience of this type of ignition, I haven't a clue where to start. Any help appreciated. I will be seeing the owner this evening so any info I will pass on. Many thanks, Andy

Title: Re: BSA B33 Magneto setup
Post by: L.A.B. on June 27, 2008, 06:40:11 PM

"E3HM" would apply to the dynamo part of it I believe?:

http://www.hawkerelectrical.co.uk/items/15-1_6-lucas-dynamo-armature-for-e3hm-dynamo.htm

Magdyno could be an MO1/? unit?:

http://www.hawkerelectrical.co.uk/pages/motorcycle_magnetos.htm

Some MO1(L) information is available here: http://www.bolsover.com/lucas/

Title: Re: BSA B33 Magneto setup
Post by: thunderbird on June 28, 2008, 06:17:51 AM

Hi i have just got my b31 going after a long rest, so may be able to help. if bike is kicking back on starting ignition may be to far advanced. i used the following settings from an old pitmans bsa manual.plug gap 18/20 thou points gap when fully open 12/15thou, ignition timing points should just start to open 7/16th " BTDC fully advanced on the compression stroke, hope this is of some help.Regards Steve

Title: Re: BSA B33 Magneto setup
Post by: Andy_G on June 28, 2008, 03:52:36 PM

Thanks ever so much chaps, I found the required info in an old Motor Cycle Data book (1960) and gave it to the fella who's bike it is. Hopefully he'll get it running sweetly once more.