To quote John:\u00a0 “Anyone who has looked closely at Japanese motorcycles from the Seventies may have noticed various numbers\/letters stamped or marked on some of its components. In some cases, these are date codes and it should be pointed out that these date codes relate to the date of manufacture of the part and not the motorcycle. In general it is normal to see a date of between 0 to 2 months before the manufacture date of the bike.<\/em><\/p>\n Before reading further, it is necessary to understand a little bit about Japanese dating practices. Since 1868, when Japan switched rulers from a Shogun to an Emperor, there have been four reigning Emperors: Meiji, Taisho, Hirohito (Showa), and Akihito (Heisei). Japan’s traditional era is based on the emperor’s reign and machines manufactured during the seventies were manufactured during the Showa reign. Hirohito (Showa) came to reign in 1926 and therefore a Gregorian date of 1973 would be the 48th year of Showa.”<\/em><\/p>\n For the Suzuki years under discussion, you then have the following Showa equivalents: 43=1968, 44=1969, 45=1970, 46=1971, 47=1972, 48=1973, 49=1974, 50=1975, 51=1976 and 52=1977.\u00a0 To further complicate matters, Japanese parts can be dated by either the Showa code or Gregorian code, and abbreviations are sometimes used as well (‘3′ rather than ’73’ to signify Gregorian 1973 for example, and ‘8’ for Showa ’48’ being Gregorian 1973). On top of all this, and to totally confuse things Suzuki went one step further and also marked parts with the actual part numbers, and then wheel rims had a different marking system completely which I’ll get to in a moment.<\/p>\n Most of the material I have is specific to the GT750, but from what I’ve seen it applies to other Suzuki models also.\u00a0 What follow are a few examples – just click on any photo to see a larger version.<\/p>\n Takasago supplied wheel rims to many Japanese bikes and had their own date stamping For the full version of what I have found so far, please check my web site at this link<\/a>.\u00a0 So there you go – now we can all sleep at night !<\/p>\n","protected":false},"excerpt":{"rendered":" One of the things that I know we all lay awake at night thinking about is ‘what do those markings on Suzuki components mean ?’.\u00a0 So to put our collective minds at ease, I have been doing some checking into … Continue reading ![\"\"](\"https:\/\/i1.wp.com\/www.oldjapanesebikes.com\/mraxl_GT_Resource\/datecode\/img\/page-1\/IMG_4797a.JPG?resize=311%2C198\")
<\/a>I have gone through my gauges for the T500, GT550 and GT750 and so far have found only one instrument that has a date stamp. Referencing the photo to the right, this gauge is off a brown face, KPH 1977 GT750 and the Showa date clearly shows this as a June 8th, 1976 date of manufacture. The others I have often have what appear to be quality control or inspection stamps, but no dates. If anyone else has additional examples I’d appreciate you contacting me.<\/p>\n![\"\"](\"https:\/\/i1.wp.com\/www.oldjapanesebikes.com\/mraxl_GT_Resource\/datecode\/img\/page-1\/IMG_4813a.JPG?resize=289%2C166\")
<\/a>Carburettors were punch stamped, and then ink stamped after 1974 (depending on the model) and used the part number\u00a0 as well as an indicator to mark left, centre or right as applicable.\u00a0 This is a GT750 carburettor from a 1977 ‘B’ and is clearly marked with a 316, which is the model number for the M, A and B GT750’s and the suffix of ’23’ which is specific to the ‘B’. The ‘R’ indicates it is the right side carburettor. Fuel cocks used a similar methodology.<\/p>\n![\"\"](\"https:\/\/i0.wp.com\/www.oldjapanesebikes.com\/mraxl_GT_Resource\/datecode\/img\/page-1\/IMG_4794a.JPG?resize=232%2C122\")
<\/a>methodology prior to 1977. So when looking at a wheel rim marked as TAKASAGO 2.15 X18 6K 103 JAPAN. it decodes as: the manufacturer, the rim size (2.15×18). and then the date code of 6K which is 1976 and the month of November, followed by the model (103 fitting the GT500, GT750 and other Suzuki models).<\/p>\n