I worked for the mid west distributor for Sekai between 1981 and 1984 (Champaign Cycles, Champaign Illinois). The 4000 and 5000 could be bought as a complete bike or frameset. The 4000 was a touring design built with Tange #2 Cro-Mo tubing. The 5000 was a racing design with Tange #1. Both of these bikes where very nice builds for mass-manufactured frames. There where built by a company in Japan which did several labels including Sekai. I am sorry, I dont remember the name of the company. Peter Davis at Champaign Cycles could give you the real details. I beleive he is still involved in the business.
FWIW, I raced on a full Super Record equipred 5000 for a number of years. Really enjoyed it.
Los Altos, CA, USA
> From: firstname.lastname@example.org
> Date: Sat, 15 Jan 2011 17:07:14 -0700
> To: email@example.com
> Subject: [CR] Curious about Sekai Professional 4000
> Recently bought a frame to replace my daily rider and know only very little about the line, just that the frames were brought into Seattle from Japan. My guess is that the frame is from the late 70s. Seems nicely made with features I like: cutout lugs, wraparound seatstays, slope-shouldered fork crown, etc. Designed for 27" wheels?
> I was hoping folks on the list might have more background or opinions about these bikes.
> Thanks for any info.
> park City, UT