...I might be wrong - it been 50 years since I dismantled a BSA twin. Pete I've just spent a couple of days measuring and shimming a Huntmaster bottom end. As has been noted the shims go between the roller bearing inner and the crank web, the timing pinion gets tightened against the crank journal o...

The Huntmaster (and BSA A10 for that matter) have a bush for the the timing side main and a lipped roller on the drive side. There's nothing 'positive' as such to locate the crankshaft and the lipped rollers don't seem mind about dealing with end-float.

SG

Charles To be clear on this tricky subject, I'm not saying I saw that re-magnetisation was un-necessary; what I saw was that the later magnetos don't suffer the same dire consequences of having an armature removed that the earlier ones do. Which salves my conscience about leaving some MO1L and K2F b...

....no matter what has been done to it, if the armature has been out of the housing, it has to be magnetized. However, one of the points I took from Charles' earlier link to the britbike forum was that the 1950s magnetos don't need a 'keeper'. Having fretted quite a lot about leaving MO1L and K2F b...

Alan - if you're going to start getting into these you might want to have a good look around the 'BSA Otter' website.
Here's a good starting point
http://www.bsaotter.com/ariel_ht_factory_build....html

SG

Frank - hope that surgery goes OK, wishing you all the best.

SG

Excellent contributions gents, many thanks.
Once I get my brain 'unfried' I look into harvesting this thread for a Club 'HowTo'.

SG

I've had this problem after fitting new camshaft bushes and pushing one fractionally too far in. I'd ease one bush out a tad (you only need a couple of thou probably) - it could just be the inner radius on the shaft (or a bush) that's binding slightly. All that matters is that the cam lobe or the ca...

Or a 'non-standard' method of reducing the end-float is to gently push the cam bushes closer together! (Or maybe just one of them...)
SG

There are at least two variations for the Ariel alloy-hub rear sprocket, one with cut-outs and one that's a disc (I've got one of each). Ariel sprockets have 47 teeth, BSA had 42. If a sprocket doesn't have 47 teeth it's not for an Ariel. If you've not found it already there's some discussion in thi...