E0 Japanese GT550 Models
The Japanese market GT550's were generally similar mechanically to variants sold a year later elsewhere, but used a unique frame numbering system. As with the GT750, one noticable difference was the 80 kph warning light.
The models themselves have a 'B' stamped after the GT550 prefix on the frame, and it appears the engines were not market specific and so would likely have had engine numbers correct for the year of manufacture globally. Note that all domestic market models are referred to as being 'B' machines regardless of the year, so the 1976 'B6' would correspond to the 'B' model sold in 1977 elsewhere. Production volumes were very small with just 1248 made in 1971, 303 in 1972 and 721 in 1973. As the engines were pulled from the same assembly line as those destined for foreign markets, it is possible to estimate that perhaps only about 3000 were sold in total for all years, making genuine JDM B variants quite rare.
Excepting differences required to meet Japanese vehicle certification/registration requirements:
- The 1971 'B' model is the same as a 1972 'J'
- The 1972 'B2' corresponds to a 1973 'K'
- The 1973 'B3' variant corresponds to the 1974 'L' model sold elsewhere in the world
- The 1974 'B4' mechanically is the same as the 1975 'M' sold outside North America, having no cross couplers on the exhaust, and having the SCEM plated cylinders.
I have no data on later models, but assume JDM models would be the same mechanically and perhaps differ only in colour selection to other markets after the 'B4'. The latest JDM model I've been able to confirm is a B6
- Common to all the Japanese models (at least through till the 'B4'), was the addition of a warning light which lit when the bike exceeded 80 kph. I have yet to find a good photo of a JDM GT550 gauge cluster that clearly shows this, but expect one will turn up eventually. The alarm lamp was triggered by a relay (part number 34990-33020 changing to 34990-32020 for the 'B3' and 'B4' models) connected to the speedometer.
- The speedometer part numbers for the 'B' and 'B2' were specific to Japan but interestingly the tachometer was the same as used in the E1 version.
- The 'B3' and 'B4' tachometers were the same as used on the 'L', 'M', and 'A' sold elsewhere, and again the speedometers were specific to the JDM market.
Other differences included:
- Both Nippon Denso and Kokusan electrical components were used in the 'B' through 'B4' models.
- Early 'B' models had a 2 bolt side stand which changed to a 3 bolt style prior to the 'B1' being released. This corresponds to the E1 export model where the change to a 3 bolt pattern occured sometime shortly after frame #19232.
|Colour codes for the B through B4 models translate (I think) as follows:
The combinations at the bottom for the various tank colour trim packages for 1971 and 1972 are : 506, 507, 508, 944, 945 and 946.
There are some Japan domestic market sales brochures at this link.
The GT750 Club in Japan web site has quite a few photos available on line of member's bikes - I'm not sure if the site is dormant or not as they have not replied to any of my emails, but several examples of Japan market only colours are shown so it is worth a look. The text below is for any Japanese owners who may wish to contact me with additional information: