Print Page - B31 1949 engine shafts

Title: B31 1949 engine shafts
Post by: Fearn80 on 18 Jan, 2025, 16:58

Hi to all

New member saying hello and after a little help.

I'm looking to find replacement engine shafts for 1949 B31 crank.

Unfortunately I'm not having much luck finding the drive side shaft. Part number
65-1128.

I have found a good used timing side shaft.

However the M21/20 drive side shaft looks almost identical to the B31 item and i have found a few of these for sale NOS.

Problem is the part numbers are different
66-0644.

So the question is does anyone know what the difference between these 2 drive side shafts are? Could it be used on B31 crank?

My very worn one could be restored by hard chroming... Or Mark at PES offered to make me a pair.

Thought I'd just try and hunt down a NOS item or a good used( not easy the used ones all seem equally worn on the journal)

Cheers
Andy

Hope this makes sense
Thanks
Andy

Title: Re: B31 1949 engine shafts
Post by: Bigsingle on 20 Jan, 2025, 07:33

Quote from: Fearn80 on 18 Jan, 2025, 16:58 Hi to all

New member saying hello and after a little help.

I'm looking to find replacement engine shafts for 1949 B31 crank.

Unfortunately I'm not having much luck finding the drive side shaft. Part number
65-1128.

I have found a good used timing side shaft.

However the M21/20 drive side shaft looks almost identical to the B31 item and i have found a few of these for sale NOS.

Problem is the part numbers are different
66-0644.

So the question is does anyone know what the difference between these 2 drive side shafts are? Could it be used on B31 crank?

My very worn one could be restored by hard chroming... Or Mark at PES offered to make me a pair.

Thought I'd just try and hunt down a NOS item or a good used( not easy the used ones all seem equally worn on the journal)

Cheers
Andy

Hope this makes sense
Thanks
Andy

Hi Andy I can't help too much, but have you tried cross-referencing with the m20/m21 check the cush drive parts are the same ??, have you looked on dragonfly. My B33 has a M20 crank modified for the B33 timing axel .Cheers.

Title: Re: B31 1949 engine shafts
Post by: Fearn80 on 20 Jan, 2025, 07:58

Hi .... Thanks for suggestions. Yup all the associated parts attached to the drive side shaft have the same part numbers from what i can tell.

Cheers
Andy

BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Fearn80 on 18 Jan, 2025, 16:58