The Keyster D3 is the same size as the 266. The K24231, 16151-275-004 (CB77) is significantly shorter and wider in diameter. It's for sale at the ebay link below if anyone is interested.
http://www.ebay.com/itm/141348262990?ss ... 1555.l2649
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Latest Registry Entry
1965 Honda CP77 — Ulsan Metro City, Rep. Korea
Restored with original parts — Owner: J. Doe