The BMW Club Vintage & Classic Register

http://www.snafu.org/restore/ - Probably the most comprehensive guide to the restoration of an Earles Fork model available on the web.

Duane Aushermann - A huge collection of 'How To...' articles and a wealth of information. Simply a site not to be missed.

www.ebay.de - German eBay

cms.bmw-einzylinder.de - A meeting point for all BMW Oldtimer enthusiasts

https://goo.gl/maps/bhD3yqkuJaJFaiUGA - Roy Deeley rebuilds pressed-up cranks:email acme-motorcycles@hotmail.com or call him on 07428 731291, his workshop is worth a visit just for the period flavour of the place.