Not likely they ever came with Concentrics. Yours will run fine with them though. 2.5 slides ought to be the size to use.


1967 BSA Wasp
1967 BSA Hornet (West Coast Model)
1967 BSA Hornet (East Coast Model)
1968 BSA Firebird Scrambler
1968 BSA Spitfire Mark IV
1965 Cyclone Competition where are you?