Classic Bikes Custom Bikes Individual Racing Bikes AJP AJS Aprilia Ariel Avinton / Wakan Bajaj Benelli Beta Bimota BMW Brough Superior BRP Cam-Am BSA Buell / EBR Bultaco Cagiva Campagna CCM CF Moto Combat Motors Derbi Deus Ducati Excelsior GASGAS Ghezzi Brian Gilera GIMA Harley Davidson Hero Highland Honda Horex Husaberg Husqvarna Hyosung Indian Jawa Kawasaki KTM KYMCO Laverda Lazareth Magni Maico Mash Matchless Mondial Moto Guzzi Moto Morini MV Agusta MZ / MuZ NCR Norton NSU Paton Peugeot Piaggio Revival Cycles Roland Sands Royal Enfield Sachs Sherco Sunbeam Suzuki SWM SYM Triumph TVS Ural Velocette Vespa Victory Vincent VOR Voxan Vyrus Walt Siegl Walz Wrenchmonkees Wunderlich XTR / Radical Yamaha Zero Video Technical
Complete Manufacturer List

Kawasaki Z2 750RS

Make Model	Kawasaki Z2 750RS
Year	1973
Engine	Four stroke, transverse four cylinder. DOHC
Capacity	746 cc / 45.5 cu-in
Bore x Stroke	64 х 58 mm
Cooling System	Air cooled
Compression Ratio	NA
Induction	4x Mikuni VM 26 SC carburetors
Ignition	Battery & coil
Starting	Electric & kick
Max Power	69 hp / 51.4 kW @ 9000 rpm
Max Torque	5.9 kgf-m / 42.6 lb-ft @ 7500 rpm
Transmission	5 Speed
Final Drive	Chain, 96 Link
Final Drive Ratio	2.80 (42 rear tooth / 15 Front tooth)
Frame	Steel double cradle
Front Suspension	Telescopic forks
Rear Suspension	Swing arm dual shocks
Front Brakes	Single disc
Rear Brakes	Drum
Front Tyre	3.25-19
Rear Tyre	4.00-18
Dry Weight	230 kg / 507 lbs
Fuel Capacity	17.7 Litres / 4.6 US gal

It is well documented that in the late sixties, Kawasaki intended to hit the market with an in-line 4-cylinder 4-stroke 750cc motorcycle. However, with Honda trumping their glory with the CB750, it was back to the drawing board. With so much design work already achieved, Kawasaki upped the ante and within a couple of years they were making their own headlines with the Z1.

Clearly though, the development work carried out in the early years on the 750cc configuration was not to be lost, and this was ultimately to result in Kawasaki developing a motorcycle to suit their own market. It is ironic that the “big four” who had such thirst for power and speed were domestically restricted to a rather conservative 750cc displacement limit.

Once the world had been won over with the Z1, Kawasaki went all out to capture the Japanese market. On the instructions of chief Engineer Ben Inamura, development work on a 750cc model was to progress. No doubt, it would have been an easy option to sleeve down the bore from the Z1’s 66mm in order to save on manufacturing costs and equally “time to market” but this was not a sensible or desirable option. Further development work required meant that production of a 750cc model would be around 6 months behind that of the Z1. Eventually a 64mm bore x 58mm stroke configuration was agreed on which demanded a new crankshaft design, together with smaller 26mm carburettors. By December of 1972, Kawasaki were ready to call a press conference at the Takanawa Prince Hotel to announce the release of the Z2 to Japanese dealers.

I have been unable to find any information regarding prototype Z2 models. No doubt test riders must have ridden test models during late 1972, but this information (to me) is unobtainable. However, it is known that 25 ‘pre-production’ motorcycles were manufactured in December 1972. Sources in Japan suggest that 15 of these were used for racing with the other 10 allocated for journalist testing prior to official release. The only ‘pre-production’ vehicles I’ve seen or heard about are No. 1 that is apparently in Kawasaki’s museum, No. 9 that I have seen in Japanese books, and No 15 of which I have been informed is in the UK.

Left - Japanese sales brochure (Front side only) from 1972.

The motorcycle on the front is almost certainly a Z1 and is clearly aimed at enticing the Domestic market for the following February

The Z1 may have had a 6 month head start regarding manufacture, but by time shipping and import control regulations had taken effect in various export markets, the Z2 wasn’t that far behind the Z1 in sales dates, probably no more than 2-3 months. Z2 manufacture commenced in late January 1973 and continued until October of that year when it was replaced by the Z2A. It was an instant success with sales outstripping the Honda CB750 by 9%. In all, 3,611 units were built in this first production run. The bike went on sale in its home market for 418,000 yen, which at 1973 exchange rates was about £700 - not too far adrift from the price of a 1973 H2A. Kawasaki claimed that the top speed was 200kph, with a SS quarter mile time of 12.5 seconds and a power output of 69bhp at 9000rpm.

Unlike the Z1 produced for 1973 in Brown/Orange and Yellow/Green, the Z2 was only produced in the Brown/Orange colours. In some ways the bike was a cross between the European and USA versions of the Z1. For example, the switchgear / headlight was UK spec, as was the seat and the fixed footrests, but the rear mudguard was the US type, as were the shocks (albeit with orange reflectors rather than the US red ones). The sidepanel badges were identical to the 900 versions apart from the cc size, and of course it had a KPH speedo with a "red line" of 80kph - Anything more than 80kph and a switch under the fuel tank is tripped and a warning light fitted on top of the headlight comes on! The only other cosmetic change would be for the eagle eyed, that being a 42 tooth rear sprocket in place of a 35 tooth Z1 item.

With regards to the speed warning set up mentioned above, a mini-loom ran from the switch in the speedometer to the speed warning unit 25025-003 under the tank. This item was never offered as a spare part but the wires were later incorporated into the Z2A instrument light loom which adopted a new part number (compared to the Z1A item) for this purpose.

As mentioned earlier, the only other major differences relate to engine internals and carburettor specifications. However, for those interested in changes within the ‘first’ model specification, the engine changed from a one piece to the 2 piece head gasket at engine number Z2E01086 (Z1E-14319). Also, the camshaft sprockets had a location mark put on them from Z2E01758 onwards. This was to provide accurate positioning for tappet clearance (the marks should level up with top face of cylider head).

Although this motorcycle is most commonly referred to as Z2, it is perfectly acceptable to refer to it as 750-RS. This is one of those bikes that officially appears to have 2 names. All Kawasaki literature refers to this model as either 750-RS or Z2 (or both) depending on what reference you are reading. Clearly, in Japan, either name is OK. Some time ago I did enquire as to what the “RS” stood for. I was originally informed that this was “Road Star” but have since been informed that it means “Roadster”. Something lost in translation perhaps but either seems OK to me!

Source by John Brookes motor info at freewebs.com