Motorcycle Repair: serial number


Question
i just bought my deceased grandfathers last motorcycle, i was mold it was a 69 Honda, sight unseen i bought it, to my surprise its all there i think and in amazing shape, few questions though serial # is ca160-10021s2. i think the second to last number is a s or a 5 hard to tell, its all wonky, not in line off set, engine number is a16oe-1002151, just want to verify what year and exactly what it is.

Answer
Brad, the bike is an early CA160 Touring 160, which was derived from adding the 160 style engine into the previously recognized 1959-65 CA95 Benly 150 Touring model. The engines are totally different but interchange into the frame with little difficulty.

http://www.cmsnl.com/honda-ca160-touring-160-1966-usa_model998/partslist/?model_ for parts references.  The center three digits, in this case 225 denote the model specific parts for the 160 version. If you look through the parts lists you may find quite a number of 200-215 coded parts, which were the original parts for this design. While they are sometimes referred to as "Baby Dreams" due to the similarity of the looks to the 250-305 CA72-77 "Dream" models, virtually no parts will interchange between them. While the models are definitely based upon the previous "Benly" name, the 160 versions did not include "Benly" (Japanese word for convenient) in the last series. There were some later CA/CD175 models, which followed some of the practices of the Benly 150-160 models, but were transitional models that moved away from their pressed-steel frame predecessors.

The engine/frame serial numbers are close together numerically, which indicates that they are the factory pairing. Honda serial number almost never match up exactly between engine and frame. Yours are almost the perfect match, differing only by one digit, which is rare. This occurred because the bike and engines were the 2,151/2 editions produced, launched in 1966. Honda was capable of producing these machines at the rate of one every few minutes, so they got to the 2,000th bike within a matter of a week or so after putting them into production. Again, the basic chassis design and many of the parts go all the way back to 1959, when the first of the 125-150 Benly twins were released and sold in the US.

It is odd to find a mis-stamp on the serial numbers, but these things can happen when you are cranking out machines at such a rapid rate. I think that the random 5 number was just a factory error.

http://www.motorera.com/honda/h0160/tour160.htm  shows the release dates started back in 1966. In many cases, some of these small-bore machines sat unsold on dealer's showrooms for several years after they were received from American Honda warehouses. So, it is possible that the original sale date wasn't until 1969 and the bike was titled as a 1969 edition, however the actual build date is back in 1966 time period.

Bill Silver