BSA C10 C11 C12

BSA C10 C11 C12 Forum => Technical Section => Topic started by: mrmend on October 21, 2020, 02:53:25 pm

Title: Crankcase cover spacer nut
Post by: mrmend on October 21, 2020, 02:53:25 pm
Hello, I am rebuilding a 1957 C12 but the long nut which holds the crankcase cover ( the cover below the carburettor, see photo ) appears to be about 1/2” short. The nut measures 2 5/8”, the cover fits perfectly around the frame tube etc. This bike came in boxes and I am wondering if I have gone wrong somewhere in my assembly.
Thanks in advance.
Title: Re: Crankcase cover spacer nut
Post by: hampshirebiker on October 21, 2020, 03:08:41 pm
I think your bolt's OK. The bottom of my cover is only about a 1/4 inch outside of the gearbox joint.
Title: Re: Crankcase cover spacer nut
Post by: camman3 on October 21, 2020, 03:17:05 pm
Yes the spacer/nut is correct....perhaps you have the wrong cover?....they vary slightly over the model range.
This is link to template of c12 version for you to confirm, should be easy to alter if that is the case

https://bsac10c11c12.co.uk/smf/gearbox-cover-templates/c12-gearbox-cover-plate-template/
Graham
Title: Re: Crankcase cover spacer nut
Post by: mrmend on October 21, 2020, 03:45:12 pm
Thanks for the replies, I think I realise what has happened. The bike came with 2 of these cover plates and both were in primer, if I lift up the cover to line it up with the long nut the cover is not horizontal where it passes over the gearbox, I think these must have been a cover copy and have been bent in the wrong place. I should have checked before painting the plates😠
Title: Re: Crankcase cover spacer nut
Post by: hampshirebiker on October 21, 2020, 03:45:28 pm
Looking again, the bend in your cover is nowhere near sharp enough. Mine's got a radius of about one inch.
Title: Re: Crankcase cover spacer nut
Post by: mrmend on October 21, 2020, 07:06:19 pm
Yes, I will spend tomorrow trying to rebend it without damaging the paint, if not it's strip the paint and start again.
Title: Re: Crankcase cover spacer nut
Post by: hampshirebiker on October 21, 2020, 07:25:51 pm
It should be flat across the top and vertically. Having flattened your plate, bend it in the zone on Graham's sketch. I don't seem able to recover the sketch. It just says "error has occurred". It might be worth posting it again on a direct reply Graham.
Title: Re: Crankcase cover spacer nut
Post by: John M on October 21, 2020, 07:53:04 pm
Graham's sketch:

https://bsac10c11c12.co.uk/smf/gearbox-cover-templates/c12-gearbox-cover-plate-template/
Title: Re: Crankcase cover spacer nut
Post by: hampshirebiker on October 21, 2020, 08:00:24 pm
Thanks John.
Title: Re: Crankcase cover spacer nut
Post by: John M on October 21, 2020, 10:29:09 pm
Mmm.... Pete's modified my link so it now doesn't work.

Here is my original link:

https://bsac10c11c12.co.uk/smf/technical/c12-crankcase-cover-template/

.. which should work.
Title: Re: Crankcase cover spacer nut
Post by: Armitage Shanks on October 22, 2020, 10:08:21 am
Strange, it works for me?
(Pete logged in as regular member)
Title: Re: Crankcase cover spacer nut
Post by: Pete on October 22, 2020, 10:11:25 am
It must be a permissions issue, I'll look into it as soon as I can. Sorry
Pete
Title: Re: Crankcase cover spacer nut
Post by: John M on October 22, 2020, 11:51:44 am
It must be a permissions issue, I'll look into it as soon as I can. Sorry
Pete

Certainly looks like permissions - us plebs not allowed.  ;D

Actual error message is: 

An Error Has Occurred! The topic or board you are looking for appears to be either missing or off limits to you.

Title: Re: Crankcase cover spacer nut
Post by: Pete on October 22, 2020, 01:08:27 pm
Does it work now John?
Title: Re: Crankcase cover spacer nut
Post by: John M on October 22, 2020, 02:30:09 pm
Does it work now John?

Works fine now Pete thanks.
Title: Re: Crankcase cover spacer nut
Post by: Pete on October 22, 2020, 04:59:47 pm
That wasn't the only thread members couldn't access. Hopefully I've sorted them all now. Thanks for pointing it out.
Pete