BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: MJM_58SR on 07 Mar, 2021, 21:21

Title: Magneto pinion
Post by: MJM_58SR on 07 Mar, 2021, 21:21
Hi
Has anyone seen this type of pinion before please?
Just wondering what it is and how to get it off
Thanks
Title: Re: Magneto pinion
Post by: MJM_58SR on 08 Mar, 2021, 09:08
I've got it off with a bit of heat but it would be useful to see if anyone recognizes the part. It doesn't have the threads for the extractor so not sure where its come from.
Title: Re: Magneto pinion
Post by: DAVE BRADY on 08 Mar, 2021, 10:02
Hi,

This looks like the pinion on my wife's A10 which has an electronic unit fitted.   As it does not need and auto A/R unit a plane pinion is used. This could also be used with a manual A/R magneto.  These seemed to come on to the scene as a replacement for the Tufnol ones.  Probably cheaper to make and nice and light.  Two threaded holes would help with extraction rather than one.  Is the small hole in yours threaded?

Dave.
Title: Re: Magneto pinion
Post by: Bess on 08 Mar, 2021, 10:33
Hi,
     As Dave says, plus is the steel tacho drive doubling up as a screw/bolt to secure the aluminium gear?

Best wishes...
Title: Re: Magneto pinion
Post by: JulianS on 08 Mar, 2021, 11:09
This is the one I bought from SRM in 2018, comes with central thread 11/16 x 20 tpi for the common BSA mag pinion extractor.
Title: Re: Magneto pinion
Post by: MJM_58SR on 08 Mar, 2021, 11:56
Hi all
Thanks for the replies. Yes the hole is threaded, the chain case screws fit so i heated the pinion a bit and then used one of those to put some pressure on it and it came off.
I've not managed to find an image of one anywhere else so far.