BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: A10 JWO on 19 January, 2018, 16:54:40

Title: 1971 OIF Thread.
Post by: A10 JWO on 19 January, 2018, 16:54:40
Every thread on my A65 is shown as Uni-thread. However the oil feed pipe is held on with a 5/16" Whitworth bolt according to my parts list..21-1973. Can anyone confirm please.
Title: Re: 1971 OIF Thread.
Post by: AWJDThumper on 19 January, 2018, 17:18:13
My 1971 parts book shows it as 21-1973 5/16" UNC!
Title: Re: 1971 OIF Thread.
Post by: A10 JWO on 19 January, 2018, 17:54:11
I have looked at Dragonflys list and they claim it is Whitworth ???. Don't want to damage anything. Will test both gingerly. Thanks for response.
Title: Re: 1971 OIF Thread.
Post by: AWJDThumper on 19 January, 2018, 18:55:56
It's been 5/16 since at least 1969 when BSA changed to unified threads - Dragonfly are simply wrong! Also, both 5/16 BSW and 5/16 UNC are 18 tpi and therefore, to all intents and purposes, identical.
Title: Re: 1971 OIF Thread.
Post by: A10 JWO on 21 January, 2018, 17:45:25
Thanks Thumper.