BSA Bantam Engine overhaul Ep 2 of 6

Classic bike engine overhaul. D3 BSA Bantam engine overhaul by Oz BSA Bantams.

[@retromechanicalengineer]

Some nifty special tools Bones, very handy. I'd love to find an original BSA layshaft bush reaming jig but I think Unicorn crap is easier to come across! Best wishes, Dean.

[@OzBSABantams]

Yep I've never even heard of anyone who's even seen one.........

[@wankj7246]

Very nice....my father own this bike...but very hard to find spare part or used part for this bike in Malaysia

[@OzBSABantams]

Hi, Thanks for the comments. If you go to www.ozbsabantams.com.au you will see my website with all the parts available for BSA Bantams. I send parts to Malaysia.

[@wankj7246]

@@OzBSABantams Thank you again

[@josephjames2335]

Hi Tony, I'm rebuilding my D3 engine and have the cases split. Can you advise how much wear is permissible in the tophat layshaft bushes before replacement is necessary? There isn't any visible wear of the bush flanges (the rim of the tophat) inside the case. But some rocking side to side play when I hold the layshaft vertically and try it in either of the two bushes with the crankcase halves on the table. Thanks Joe

[@OzBSABantams]

Hi Joseph..........firstly put the layshaft only in both cases and bolt them up. Make sure you have the dowels in too. With the cases bolted up get something like a scriber and put it in the centre drilling on the end of the layshaft. Now try and move the layshaft radially. If you are able to detect any movement then change the bushes. Axial movement between the bush flange faces shouldn't be more than 1mm. This is also how you check after bush replacement.

[@josephjames2335]

​@@OzBSABantams Thank you Tony, that is really clear. Appreciate the help. I have a running 1950 rigid D1 surviver with a tired engine, the D3 engine is a spare I'm rebuilding first. Enjoyed the rigid D1 recommission you did. Have learned a lot from your channel. Cheers Joe