BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: spike123 on 02 Jul, 2023, 01:00

Title: Rear brake
Post by: spike123 on 02 Jul, 2023, 01:00
Hi guys
My 1971 a65 , I've just put the brake arm and rod on and the rod rubs on the shock lower bolt, I have had nothing but problems with the spring on the arm not fitting correctly, this was the same for my 1969 a65 , so the brake arm is sitting about4.00 o'clock and looks as if it should be lower to miss the bolt and thoughts
Title: Re: Rear brake
Post by: JulianS on 02 Jul, 2023, 10:20
Use the modification in the attached service sheet from June 1971 to the rear brake as fitted to the later OIF twins.

Note that BSA subsequently cancelled the mod for the A75 and OIF singles.

Bike image from 1972 BSA catalogue.
Title: Re: Rear brake
Post by: spike123 on 03 Jul, 2023, 03:01
Thanks for the info
Title: Re: Rear brake
Post by: Allan G on 03 Jul, 2023, 20:02
Bit more to it than just that. The brake cam and the arm are unique to the upside down - vs - upright models.

Unlike the pre oif bikes that have the 8pt spline with a variety of adjustment, the oif type either has a square profile for the downward mounting, or a circle with two opposing flats for the upright version. (This profile is on BOTH parts)

Whilst you could put the upright version on a downward cam, the brake would be ineffective as the cam would point forward of 90°.

HTH