XR evolution
A step ahead
The XR23 featured a stepped cylinder
design because that lowered the centre of
gravity and moved it forward. Additionally,
it was good for cooling because it freed
the area just behind the radiator – if the
front cylinders are high, there is less room
for airf low. It also meant Suzuki race
mechanics could extract the transmission
from the right side, without the need to
remove the engine from the frame. This
proved a great asset, allowing gearbox
ratios to be swapped in under 20 minutes.
Crank call
The engine had just two crankshafts, one
for each pair of cylinders, rather than four
separate ones as on the RG500. Two 36mm
magnesium Mikuni carburettors were
mounted on each side of the engine, to feed
the rotary valves splined to each end of
the cranks, with the seven-port cylinders
responsible for the harsh crack to the
Suzuki’s engine note in those stinger exhaust
days. Ignition was via a Nippondenso CDI,
with the cassette-type six-speed gearbox
mated to a multiplate dry clutch.The frame remains the same
The ultra-powerful engine was installed in
an only slightly beefed-up version of Suzuki’s
rather flimsy-looking twin-shock tubular
steel frame as used on the RG500, fitted with
bracing struts for the front cylinder head
mounts and a 37mm Kayaba air-damped
telescopic fork set at a rangy 27.5o. The same
pair of 295mm f loating steel discs with
twin-piston Tokico calipers as on the RG500
were initially mounted up front, with a single
240mm ventilated rear, providing barely
adequate stopping power.It became the fi rst
modern racer to break
the 300km/h mark