Thanks to Tom Martin, contributor to Bike Forums for following information.
Tom Martin, mentioned in the quote, appears to be a
respected source of information on bicycle history. His expertise is in the bikes from the boom era. However, the guide may not cover every possible aspect or detail of Centurion serial numbers. As a result, it was compiled with input from Centurion owners and industry experts. Subsequently, this makes it a valuable resource for enthusiasts looking for information about Centurion bicycles and their history.
CENTURION MODELS
Centurion models manufactured in Japan between 1980-1990 use a serial number format WXYZZZZ with: W = a letter. Unfortunately, the purpose is uncertain. So, it possibly indicates a manufacturer or Centurion; X = a number, indicating the calendar year of manufacture.
Y = a letter, indicating the fortnight of manufacture (A = wk 1 & 2, B = wk 3 & 4, etc.) ZZZZ = four digit number. Most likely, indicating frame number during fortnight of manufacture. N4E0283, as an example, would indicate this is the 283rd frame made during the period of weeks 9-10 in 1984.
Other Centurion Manufacturers
CENTURIN (USA) had multiple factories that built the bikes for Centurion they can be: F (1), Katakura, Matsu****a, Mikki, N(1), Tano, U(1).
F(1): Fymmxxx(xx) Unknown manufacturer. Format seen mainly on 1980s Centurion and Diamond Back, so may be Fairly, a known supplier to Western States Imports.
KATAKURA (Japan): KMyxxxxx Format easily confused with Kawamura.
MATSU****A/NATIONAL (Japan): yMxxxxx
MIKI (Japan): MyFxxxx
N(1) (Japan): NyFxxxx Manufacturer unknown. Interestingly, some members believe that the ‘N’ prefix designates National. However, given that Panasonic and the Japanese manufactured Schwinn’s that came from Matsu****a/National do not use this format, it seems unlikely.
TANO (Japan): not yet decoded
U(1)
U(1) (?): Uymmxxxxx Manufacturer unknown. Interesting to note, these codes started appearing on Centurion and Diamond back models in the very late 1980s. However, it is known that China Bicycle Company started supplying entry level models to Western State Imports at this time.
For one thing, this was just before acquiring WSI in late 1989 and this would appear to be the logical manufacturer. Conversely, bicycles with this S/N format have been reported with Made in Taiwan labels and CBC was located in China.
Legends for Underlined data fields
F indicates an alpha character designating the fortnight (i.e. A= weeks 1-2, B=weeks 3-4,….Z = weeks 51-52)
| A | B | C | D | E | F | G | H | I | J | K | L | M |
| 1,2 | 3,4 | 5,6 | 7,8 | 9,10 | 11,12 | 13,14 | 15,16 | 17,18 | 19,20 | 21,22 | 23,24 | 25,26 |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
| 27,28 | 29,30 | 31,32 | 33,34 | 35,36 | 37,38 | 39,40 | 41,42 | 43,44 | 45,46 | 47,48 | 49,50 | 51,52 |
M indicates an alpha character designating the month (i.e. A = January, B= February,… L = December)
| A | B | C | D | E | F | G | H | I | J | K | L |
| Jan | Feb | Mar | Apr | May | June | July | Aug | Sept | Oct | Nov | Dec |
YEAR DESIGNATION
Y indicates an alpha character designating the year . The year that corresponds to a particular alpha character can vary significantly. So, the specific convention will be listed under the manufacturer entry.
mm indicates two numeric characters designating the month (i.e 01 = January, 02=February,….. 12= December)
y indicates a numeric character designating the last digit of the year (i.e. 1 = 1971 or 1981, 2 = 1972 or 1982, etc.). With such codes, you have to determine the decade based on frame characteristics, components, etc.
yy indicates two numeric characters designating the last two digits of the year (i.e. 81 = 1981, 82= 1082, etc.)
THE SEQUENTIAL FRAME NUMBER
xxxx indcates a numeric characters designating the sequential frame number within a the fortnight, month or year. However, this number string is typically four to six characters in length but can vary. Of course, the guide is not necessarily comprehensive, as it only represents what has been collected and decrypted.
Some Examples:
Example #1
1980 LeMans with SN: N0H2264
can be broken down this way
| N | Denotes the unknown manfacturer that built the bike but it is known they stamped an N |
| 0 | indicates its a model year that ends in a 0 Centurion was started in 1969 so it could be 1970, 1980 and as they were stopped after 1989 there was no 1990 models in the US (other countries still had them not sure the SN info for the non U.S. Imports. Given the componets and the graphics its a 1980 built which could be a 1980 or 1981. |
| H | indicates fortnight week H which was week 15 or 16 which would be around the last week of March or first week of April. given it was made that early in the year it is probably an 1980 model. if it was made toward the end of the year then it would probably the next years model |
| 2
2 6 4 |
Sequential numbering of frames in the given time frame |
Example #2
1987 Ironman Expert SN:N7B6800
| N | Denotes the unknown manfacturer that built the bike but it is known they stamped an N |
| 7 | Denotes year ended in 7 so 1977 or 1987. Given its a Ironman it has to be 1987 |
| B | week 3,4 of 1987 makes it at the end of January in 1987.given color scheme it is a 1987 Model |
| 6
8 0 0 |
Sequential numbering of frames in the given time frame |
Example #3
1987 Ironman Master SN:N6M9100
| N | Denotes the unknown manfacturer that built the bike but it is known they stamped an N |
| 6 | Denotes year ended in 6 so 1976 or 1986. Given its a Ironman it has to be 1986. |
| M | week 25 -26 of 1986 makes it at the beginning of July in 1986.given that there was no Master Ironman in 1986 the bike is a early 1987 Model |
| 9
1 0 0 |
Sequential numbering of frames in the given time frame |
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