The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: coater87 on 07.02. 2016 08:26

Title: Primary chain size confirmation
Post by: coater87 on 07.02. 2016 08:26

 Quick question.

 I believe the stock primary chain on a SA bike is a 428 chain.

 That is going by the bits of chain and sprocket that came in the pillow cases full of parts. I know their was som Japanese parts mixed in, and just want to be positive 428 is correct for the BSA.

 Lee

Title: Re: Primary chain size confirmation
Post by: Billybream on 07.02. 2016 09:17

Primary chain size is 1/2 x 0.335 x 0.305, 69 pitches. Type 428 is correct.

Title: Re: Primary chain size confirmation
Post by: chaterlea25 on 07.02. 2016 12:38

Hi Lee,
Usually the chain has to be an original style with narrow sideplates, the "H" chains will foul the rear primarycase
Make sure it is a quality made chain not industrial type,
I have been fitting "Regina" brand chains for some years now
Some A10's were lower geared and used a 69 link chain that needs a half link  *sad2*
70 links is correct with 21(?) 22 & 23 tooth engine sprockets

HTH
John

Title: Re: Primary chain size confirmation
Post by: coater87 on 08.02. 2016 03:56

 Thanks guys,

 I suddenly had a moment of uncertainty, and did not want to buy a bunch of stuff and then find it is not right.

 Lee