1955 BSA A7

[georgecat]

Hi fellow brit iron fans.
A bit of advice please. I recently bought a BSA A7 in fantastic condition with the engine running and sounding very nice.
However.... when I start it now I have a loud rattle, not a knock like big ends, I've also noticed very fine white metal splinters on the sump magnet, not many though . Could it be the main bearings? if so how easy are they to replace? does it need a complete engine out strip down? where do you suggest I get replacements if it is these that have failed?
Sorry for lot's of questions but I'm new to British bikes
Thanks very much

[L.A.B.]

Difficult to say really...as a rattle could be anything?

Are you certain that this noise is coming from the bottom end?

It would certainly be necessary to strip the engine to replace the main bearings (I would expect to hear a rumble noise from the drive side bearing), the timing side one being a plain bush. The crankshaft may have to be re-ground and an undersized main bearing fitted, but this is nothing but guesswork at this stage.

For any engineering work and parts I suggest you try SRM Engineering: http://www.srm-engineering.com/

Or for parts

http://pages.eidosnet.co.uk/~canddautos/

http://www.draganfly.co.uk/main.html

[georgecat]

Thanks for that, I've tried putting a screw driver to my ear and the engine to find out if I can locate the exact noise but I am struggling to locate it ie top or bottom. Would the tiny splinters of white metal on the sump magnet necessarily mean a failure?
Regards.

[L.A.B.]

Would the tiny splinters of white metal on the sump magnet necessarily mean a failure?

You could monitor the situation?
If you keep finding metal splinters then something would appear to be breaking up?
But I wouldn't leave it too long before doing something if you keep finding them, -especially if the rattle gets any worse?

[georgecat]

Thanks.