BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: EDDIE SIMPSON on 04 Apr, 2020, 23:25

Title: b31 alternator help wanted
Post by: EDDIE SIMPSON on 04 Apr, 2020, 23:25
hello, any one can help me with spacer 42 96 which is the crankcase spacer before engine sprocket. dimensions maybe?
Title: Re: b31 alternator help wanted
Post by: EDDIE SIMPSON on 09 Apr, 2020, 22:50
well shaft o/d measures 1 inch and the case hole measures about 1 1/4 inch so i will have to make something up using trial and error
Title: Re: b31 alternator help wanted
Post by: DAVE BRADY on 10 Apr, 2020, 07:55
Hi Eddie,

Is the spacer the same as an A10 or thinner/wider? 

Dave.
Title: Re: b31 alternator help wanted
Post by: EDDIE SIMPSON on 10 Apr, 2020, 22:21
hi dave,
as you know i have quite a few a10 transmission bits but nothing fits.
does the spacer act as the oil seal? so what is the clearance between spacer and crankcase?
i m out of my comfort zone with singles but its coming along.
Title: Re: b31 alternator help wanted
Post by: DAVE BRADY on 11 Apr, 2020, 07:23
Morning Eddie,

Have a look on the Draganfly website.  It has the parts diagrams and numbers for lots of bikes including the B31/33.  I just had a quick look and could not see a spacer. Two bearings on the drive side though, so no wonder they last a long time.

Dave.
Title: Re: b31 alternator help wanted
Post by: JulianS on 11 Apr, 2020, 11:35
This cross section from the B31/33 owners instruction manual might be of interest.
Title: Re: b31 alternator help wanted
Post by: EDDIE SIMPSON on 11 Apr, 2020, 20:20
thanks julian and dave,
your a great help as always.
i can now see there is no bevel on the bearing side and little clearance in the cases and on the shaft.
i will have to make something that will fit on the lathe next week. i found that triumph pre unit engine sprockets fit but different shoulders so would have to customise the width anyway. will search for this manual as well.
Title: Re: b31 alternator help wanted
Post by: EDDIE SIMPSON on 13 Apr, 2020, 12:35
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Title: Re: b31 alternator help wanted
Post by: Andy Haney on 14 Jun, 2020, 08:41
Hi Eddie
I am also fitting the triumph  20t sprocket to my b33 alternator, therefore would really appreciate the dimensions  of the spacer you have made, so I can try get one made. I have tried purchasing the original to get it shortened  but found no suppliers . The parts manual details for the spacer is  42-96 "engine  sprocket distance piece" for the original 19t sprocket.
Thanks
Andy ps. I sent you a PM incase you did not see this