Italjet Dragster 2022, Maintenance Manual

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A = 0.01 mm
B = 0.01 mm
C = 0.10 mm
D = 0.06 mm
Inspecting the crankcase halves
•
Before checking the crankcase halves, thoroughly clean all the surfaces and the oil pipes.
•
For the crankcase half on the transmission side, take particular care when handling the
housing and hoses for the oil pump, the duct with the by-pass valve and the main bushings.
•
As already described in the lubrication chapter, it is especially important that the by-pass
valve housing shows no wear that may impair the proper sealing of the lubrication pressure
adjustment ball.
•
<DIV class=CNT_SUMMARY title="Testo Breve (<4000 car.)">Check that the surfaces are
free from dents or deformations, with special attention to both the crankcase coupling and
the cylinder-crankcase surfaces.
•
<DIV class=CNT_SUMMARY title="Testo Breve (<4000 car.)">Defects in the crankcase
coupling gasket or the surfaces indicated in the figure can cause a drop in the oil pressure
and affect the lubrication pressure for the main bushings and the connecting rod.
•
<DIV class=CNT_SUMMARY title="Testo Breve (<4000 car.)">Check that the surfaces that
limit crankshaft axial clearance show no signs of wear. To measure and check sizes follow
the procedure described previously for checking crankshaft axial clearance and dimensions.
Inspecting the crankshaft plain bearings
•
In order to correctly lubricate the bushings, it is necessary to have both optimal lubricating
pressure and a good oil flow rate; this implies that the bushings must be positioned correctly
so as not to obstruct the oil supply ducts.
•
The main bushings comprise two half-bearings. The two half-bearings for the left crankcase
bushing (variator side) are plain with holes. The two half-bearings for the right crankcase
bushing (flywheel side) have holes and a central groove.
•
The oil supplying channel section is also influenced by the depth to which the bushings are
driven compared with the crankshaft axial clearance of the limiting surface.
CAUTION
THE MAIN BUSHINGS SHOULD BE FITTED WITH THE COUPLING AREA FOR BOTH HALF-
BUSHINGS PARALLEL TO THE CYLINDER SUPPORTING SURFACE AND WITH THE HOLES OF
THE LUBRICATION GROOVE PERFECTLY CENTRED.
•
Measure the bushings diameter at the 3 positions indicated in the figure.
•
Bushings are divided into 3 categories according to their thickness.
RED TYPE: 2.005 - 2.010
BLUE TYPE: 2.010 - 2.015
YELLOW TYPE: 2.015 - 2.020
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