BSA Owners' Club Forum

The BSA Workshop => Singles => Topic started by: AdrianS on 06 February, 2018, 18:38:04

Title: B40 swing arm - quick question
Post by: AdrianS on 06 February, 2018, 18:38:04
Hi,
Just had my seized swing arm sorted - only took 2 months but now bike is ready to reassemble. The swing arm pivot had to be pressed out and a new pivot fitted plus bearings in the arm.

I didn't make a note of the fittings at each end of the swing arm. I've got 2 bolts with grease nipples on, one longer than the other and also got a spacer. Can anyone let me know which side the longer bolt and spacer goes. Can't seem to find any drawings confirming the position!

Cheers
Title: Re: B40 swing arm - quick question
Post by: Phil C on 06 February, 2018, 21:27:31
Hi Adrian,  Maybe a silly question, but have you checked the drawing in the library section?  Phil.
Title: Re: B40 swing arm - quick question
Post by: AWJDThumper on 07 February, 2018, 09:07:00
I'll have a look at my B40 later because I can't think offhand why the two bolts are not the same length. However, from the parts diagram, the longer bolt appears to be on the nearside (LHS). There is a washer shown on the RHS but not sure where this goes without looking at my B40. However, there may be a shim required between the frame and the swinging arm to limit lateral free play.
Title: Re: B40 swing arm - quick question
Post by: AdrianS on 07 February, 2018, 10:02:23
I think the lateral play is taken up by the shim between the swing arm and frame on the drive side.
I think the spacer goes on the drive side as I've looked at a few pictures and no spacer appears on the right side of the bike. The parts drawing is not very clear about the spacer and the part numbers for the 2 bolts are different
Title: Re: B40 swing arm - quick question
Post by: JulianS on 07 February, 2018, 10:27:26
left side bolt is the long one on the B40.

Thrust washer on right side.
Title: Re: B40 swing arm - quick question
Post by: AWJDThumper on 07 February, 2018, 16:57:11
The only reason I can see that the LH bolt is slightly longer than the RH bolt is to accommodate the stop light switch mounting bracket. The C15 used the same bolt on both sides as did I on my B40. I don't think it matters which side the thrust washer or shim goes because it's not very thick - I beleive it's only there to take out the lateral free play.