The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Nomad54 on 29.02. 2024 22:12

Title: Engine bolt configuration
Post by: Nomad54 on 29.02. 2024 22:12
Silly question guys but I got a new set of engine bolts for my A10 swing arm model and have worked out most of the positions but there is one part left that I can't figure out where it goes. It is the nut with extended sleeve. I think it goes somewhere near the front left hand side but not sure. Any diagrams or pictures would be greatfull.
Cheers  Tom
Title: Re: Engine bolt configuration
Post by: Catz on 01.03. 2024 06:54
This any good?
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a710-b3133-c101112-m202133/engine-gaskets-gearbox/crankcase-abcm/pre-unit-a-group-crankcase/
Title: Re: Engine bolt configuration
Post by: CheeserBeezer on 01.03. 2024 08:09
This shows positioning of all engine bolts. The nut is item 32
https://sites.google.com/site/priorymagnetos/frame-parts-inc-engine-and-gearbox-mounting-bolts
Title: Re: Engine bolt configuration
Post by: limeyrob on 01.03. 2024 09:09
Its goes under the dynamo on the front engine plate where there's not much room for a nut.  I thought this was an easy question so I googled "A10 engine images" and out of 10 I found including "restored" bikes not one had it fitted!  Try the top and 2nd stud down and see where it fits best, I seem to recall its the 2nd stud.
Title: Re: Engine bolt configuration
Post by: CheeserBeezer on 01.03. 2024 20:26
According to the parts books, on both the engine and frame pages, it appears to be on the uppermost stud of the three studs which attach the dynamo plates to the crankcase halves. I believe it is there so that it extends beyond the dynamo cover so it is possible to use a spanner (wrench to our U.S.A. friends) to remove it. If it was a standard nut there would be no space to get any movement on a spanner.
Title: Re: Engine bolt configuration
Post by: Russ on 01.03. 2024 22:35
Showing position on my Plunger Frame.
Title: Re: Engine bolt configuration
Post by: trevinoz on 01.03. 2024 22:42
Andrew and Russ are correct.
Title: Re: Engine bolt configuration
Post by: Swarfcut on 02.03. 2024 09:04
  CB uses the word "Spanner" which us limeys would reckon to be either an open ended or ring type. The access to that stud is easy with a modern day socket, but back in the day that was not what the average  owner had to hand. This long nut enables the standard open ender in the standard toolkit to do the job.

 But in the usual assembly process a standard nut is fine, as the dynamo can go on after the engine plates. The only reason you'd need access from time to time is to check tighten with a standard spanner and the dynamo in place. These days a thin wall socket does the job.

 The term is also used as a tem of abuse in some circles, generally to draw attention to a person's failing in completing an important task. Example... "Why did you do that, you t*rucking spanner? 

 Swarfy.

 *Typo.
Title: Re: Engine bolt configuration
Post by: CheeserBeezer on 02.03. 2024 20:43
  CB uses the word "Spanner" which us limeys would reckon to be either an open ended or ring type. The access to that stud is easy with a modern day socket, but back in the day that was not what the average  owner had to hand. This long nut enables the standard open ender in the standard toolkit to do the job.

 But in the usual assembly process a standard nut is fine, as the dynamo can go on after the engine plates. The only reason you'd need access from time to time is to check tighten with a standard spanner and the dynamo in place. These days a thin wall socket does the job.

 The term is also used as a tem of abuse in some circles, generally to draw attention to a person's failing in completing an important task. Example... "Why did you do that, you t*rucking spanner? 

 Swarfy.

 *Typo.
The standard BSA tool kit did not contain sockets, nor were they as commonly used then as they are now... that was my point. Sorry if I didn't make that clear!
Title: Re: Engine bolt configuration
Post by: Rex on 02.03. 2024 22:49
I can just recall a time when socket sets were unusual and rare, and most relied on good old box spanners.
Kamasa changed that.
Title: Re: Engine bolt configuration
Post by: Worty on 03.03. 2024 18:43
At risk of sounding a spanner myself, on my s/a there is an elongated nut that fits in the recess of the crankcases just in front of the cylinders BUT, from memory, the elongated nut is still recessed so would need a thin walled socket to get to it.  I'm presuming the standard toolkit on the s/a would have a box spanner that would reach it, or have I simply made all of this up and need to take my tablets *????* *eek* *dunno* *dunno*
Title: Re: Engine bolt configuration
Post by: trevinoz on 03.03. 2024 23:50
Worty, I think that you will find that nut is the one under discussion.
Many people think that it goes where yours is but they are wrong.
Title: Re: Engine bolt configuration
Post by: Worty on 04.03. 2024 08:05
Worty, I think that you will find that nut is the one under discussion.
Many people think that it goes where yours is but they are wrong.

Ahhhhh, right, so the bolt goes in the recess and the long nut sticks out t'other side - that makes a lot more sense.  I got the bike with the nut in the recess, and RM put it back that way when he *rebuilt* the engine, so I assumed that's how it went. *dunno* *dunno2* *dunno* 

Every day is a school day - although I never really went that much *ex*