magneto gear question

[SunbeamS7]

G'day fellow Douglas owners,
i am having an EIC magneto rebuilt for my 1924 TS. The re-builder (whom i have also bought the magneto from)  has queried if  the required 50 tooth drive gear for the magneto should have a "shoulder" on the drive gear (it moves the gear @ 1/4 inch away from magneto-towards the engine gear train) where it mounts on magneto tapered shaft, or-- no shoulder and it therefore sits up tighter against the magneto (away from engine gear train)? This one has me baffled as i havent (yet)  seen any reference to differing magnetos gear drives (ie: shoulder/no shoulder) regarding a TS.
any and all help, greatly appreciated.
regards,
bryan

[Jim]

G`day Bryan the only magneto gear that I have seen has a boss that is 3/4 inch diameter and stands out about 1/4 inch from the gear.
 I don`t think a gear without a boss would fit in the case, regards Jim

[Jim]

P.S if I was any good I would post a photo

[Hutch]

Hi Bryan and Jim,

There is a "shoulder" on the  2 3/4 hp magneto gears I have. It is about 7/32" in height - so hence moves the gear approximately 1/4" away from the magneto as you mentioned. Everything appears to line up well (i.e. with the idler gear) using Bosch ZA2 and EIC A2 magnetos.

Picture A shows the side of the gear towards the magneto and picture B is the side towards the timing cover.

Cheers

Ian

[SunbeamS7]

G'day,
I just wanted to say thank you very much for taking the time and trouble to get back to me re: TS magneto drive gear type, your efforts and knowledge are greatly appreciated.
If i may, the irony is not lost on me, how the application of modern technology (internet etc) is being used to keep 100 year old motorcycles running! The vast amount of knowledge contained in this forum is, nothing short of, astounding.
Regards and thanks to all.
bryan