GRAUPNER heim UNI-Mechanik 2000 Mode D'emploi page 61

UNI-Mechanics 2000
bearing you must use two flat-ended mandrels, so that you can distribute the pressure evenly
over the outer and inner rings of the two ballraces, in order to avoid stressing the bearings.
There is a danger of damaging the bearings when tightening the crankshaft nut, but you can
avoid this by tightening the pinion only moderately hard at first, before pressing the bearing into
place. When the clutch is fitted on the crankshaft (see following section), apply thread-lock fluid
to the threads, press the inner bearing rings firmly against each other, and rotate the pinion
slightly in the threads to adjust the position of the outer bearing rings until the bearings rotate
freely in their installed state.
Note that different centrifugal clutches are required for different motors: the standard centrifugal
element 4448.79 is partly machined away internally, and features slightly shorter clutch shoes
than the non-relieved centrifugal element 4448.79A, which is used for lower-revving motors (15
cc two-strokes).
Remove the nut from the crankshaft (leaving the thrust washer supplied with the motor in place),
then fit the following parts on the crankshaft in this order: clutch bell, split taper collet 4448.77,
clutch element 4448.79 or 4448.79A and cooling fan 4450.2; now fit the crankshaft nut and
tighten it fully. Attach a linkage ball to the outermost hole in the carburettor arm using an M2 x
10 screw and nut.
Notes:
Two types of pinion are used in the metal clutch bells of the UNI-Mechanics 2000, and they
differ in height: the current version is 10 mm high, whereas the older version is 14 mm high. If
your pinion is the 14 mm version, use the (thinner) washer 4450.56 instead of the thrust washer
supplied with the motor, and swap over the right and left motor mounts.
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