A Field Guide to the Suzuki GT550
Model Year 1973 (K)
Please refer to the Country Specific Versions section for additional information about machines sold into your market.
Changes:
- A stainless steel disc brake ( 298 mm diameter) replaced the duplex drum brake. Specific to the 1973 model year only, the master cylinder had a solid cast brake fluid reservoir.
It is worth mentioning, that the master cylinder for the GT550 and GT750 look quite similar, however the dual front disc GT750 master cylinder has a 'D' stamped on the underside as covered in the Suzuki Disc Brake Manual, which can be viewed at this link.
- A warning label (68319-19000) was added to the fuel tank (for models K through B) concerning potential damage which could be caused by brake fluid.
- Along with the usual Showa front forks, Kayaba forks were also installed - there is no data to confirm whether this was done on an 'as required basis' or was market specific.
- Motor housing side covers now had glued, embossed "SUZUKI" labels.
- There were no changes to the transmission or final drive gearing ratios.
- the seat was the same as used for the 'J'.
- Note that the stainless steel trim was all in one piece and completely around the seat - this changed in 1974.
- Some countries had a front brake switch fitted, however this was not fitted as standard although the wiring harness had provision for the addition of a switch. The switch location on the underside of the master cylinder just had a blanking plate (57481-18600) fitted in most markets.
- Ignition, starter motor, alternator and regulator by both 'Kokusan' and 'Nippon Denso' - I have no data on whether this was market dependant.
- From engine 27536 onwards a new rotor was fitted to the Nippon Denso alternators.This is detailed in Radco service bulletin #137 available on this page.
- a change was made to the primary drive gear lock washer and key as detailed in USA Suzuki Service Bulletin #8 may be viewed at this link.
- the press fitted SRIS valves were changed to threaded units at engine 23036. This is detailed in Radco service bulletin #115 available on this page.
- The Mikuni VM 28 SC round slide carburettors changed to a 'low top' version during the 'K' production at frame 30716. Russell Armour has provided a few photos highlighting some of the features of the later style carburettors - just click on the image stack below.
- Throttle slides were 'handed' with the locator pin for the right side carburettor being on the opposite side to the middle and left carburettors
- Note there is still a lack of clarity about which carburettors were fitted and where. The Suzuki Service Data manual for 1973 lists a 34012 for non-EU countries and a 34600 for EU countries having different slide cutaways, different jet needles, pilot and main jets. The only parts manual I've been able to find does not list the 34600 carburettor - I'm sure additional material will surface over time.
- Later style 'low hat' differences include: a change to a fibre gasket in cap (some were fitted with o-rings), o-rings added to other fittings, no needle extension on the needle jet.
Painted parts: Tank, side covers, fork ears, headlamp bucket
Colours (varied by market):
- Hermosa Blue (Purple Blue) metallic (Suzuki paint code 705)
- Grace Lime Metallic (Suzuki paint code 278)
Both colours received the same dark green stripe kit on the fuel tank.