NUMBER EIGHT
n the height of the two-stroke era, if
you wanted a four-stroke motocross
bike to be competitive, the trick was
to shoe-horn an XR motor into a more
modern frame. However, to run in the twin-
shock class in current day VMX, modern
frames just won’t do. Peter Mackley was
planning on building a frame from scratch,
but after some research he learnt about
C&J Racing Frames. “They’re a known frame
and supposed to handle good”. So he
bought one and set out to build the best
four-stroke VMX racer money could buy…
But let’s back up a bit... Peter is no
stranger to big four-stroke motors nestling
in smaller chassis. In the late 70s Peter was
riding the latest two-stroke machinery
in the form of the Honda CR250 Red
Rocket, but his preference was for the
torque of a four-stroke lump. So began
his experimentation with big thumpers
transplanted into other frames. First up
came an XL250 lump in a RM250A chassis,
but the XL proved a bit weedy. Next came
a Yamaha TT540 motor shoe-horned into
an RM400 frame. A succession of other
specials (including a Mugen XR500 engine
in an RM465 chassis and a works Honda
tribute built around a 1981 CR450 motor
in a 1980 CR250 frame) spewed forth from
Peter’s workshop over the next thirty years,
but seeing a few XR500 specials gave Peter
the idea of building his own.
Peter owns and operates Custom
Chambers; a custom motorcycle exhaust
shop in East Tamaki. He’s not one to
compromise, so when it comes to building
his own bikes, rather than buying not-
quite-right parts, Peter had most of the
components custom made for the job.
The hubs, the tank and the triple clamps
were all custom made to his exacting
specifications. Even the bespoke Öhlins
shocks were made in America (although
Peter later learnt that Robert Taylor of
Kiwi Suspension Solutions could have built
and supplied the same units locally). The
parts he did buy were the best available,
and Peter went to great lengths to source
all brand-new components, right down to
original Honda engine parts.
KIWI RIDER 55