The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Goldy on 14.12. 2010 16:24

Title: Big End diameter
Post by: Goldy on 14.12. 2010 16:24

Having spent the first part of my working life measuring in inches and the remainder in millimetres, I seem to be confused. Can someone tell me if 1.460 inches is the standard big end diameter or the 10 thou undersize. Thanks lads.

Title: Re: Big End diameter
Post by: MG on 14.12. 2010 16:54

1.460inch is the standard diameter on the small journal cranks.

Title: Re: Big End diameter
Post by: A10Boy on 15.12. 2010 09:13

Good info here.

http://www.srmclassicbikes.com/technical/bsa-a7-a10-big-end-journal-sizes (http://www.srmclassicbikes.com/technical/bsa-a7-a10-big-end-journal-sizes)

Title: Re: Big End diameter
Post by: larryc on 18.07. 2015 11:18

My shells are stamped 1454, these are the non-drilled A7 from a 52 plunger, the cranks are not oval but there are score marks so they are going for a re-grind, the 1454 seems to be between std and 0.010" should I be looking for some -20 before the grind?

Title: Re: Big End diameter
Post by: muskrat on 18.07. 2015 14:32

G'day Larry.
I'm not sure if those stampings are referring to the size. If your crank is std small journal 10 thou under should clean up the journals. Best check with the grinder first.
Cheers