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Kawasaki Z2 750RS
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Make Model |
Kawasaki Z2 750RS |
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Year |
1975 |
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Engine |
Air cooled, four stroke, transverse four cylinder. DOHC |
|
Capacity |
746 |
|
Bore x Stroke |
64 х 58 mm |
|
Compression Ratio |
|
|
Induction |
4x Mikuni VM 26 SC |
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Ignition /
Starting |
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|
Max Power |
69 hp @ 9000 rpm |
|
Max Torque |
5.9 kg-m @ 7500 rpm |
|
Transmission /
Drive |
5 Speed /
chain |
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Front Suspension |
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Rear Suspension |
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Front Brakes |
Single disc |
|
Rear Brakes |
Drum |
|
Front Tyre |
3.25-19 |
|
Rear Tyre |
4.00-18 |
|
Dry-Weight |
230 kg |
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Fuel Capacity |
|
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Reviews |
freewebs.com |
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
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