I have owned 2 Durkopps- one from the Heinz Linke collection out of Cleveland, and one from an old-time racer from Minneapolis Glenn Carlson. Glenn's was sold to him by six-day racer Charlie Winters (?) when charlie came to the Minneapolis convention center for a six-day event.
As I recall the Linke machine was a light aqua blue with a headtube decal, but drilling for a badge (?!). It had a very laid-back seat tube which was suitable and necessary for the old very steeply banked six-day tracks of the time. It also had a series of drill holes in the rear dropouts- very racey! The Carlson Durkopp is pictured below.
Also pictured is a shop-oriented adjustable stem and seatpost and an old Durkopp wheel with painted flanges which was common for them.
http://www.velostuf.com/
John Barron Minneapolis http://www.velostuf.com
Message: 3 From: GPVB1@cs.com Date: Tue, 19 Mar 2002 13:29:56 EST To: classicrendezvous@bikelist.org Cc: OROBOYZ@aol.com Subject: [CR]Re: Durkopp
Dale and all:
My understanding is that Durkopp was one of the premier makers of six-day bikes back in the time period you mention, and was located in Germany.
As you noted, their hubs were more expensive than even the FBs....
I've seen one Durkopp bike. It was in Cleveland, and was one of Heinz Linke's bikes.
John Barron may be able to shed more light on this maker. JB...?
Cheers,
Greg