VESPA 946 E4 EMEA 2021 Manual page 37

Vespa 946 E4-E5 EMEA-USA-ASIA (2021-)
- The section of the oil feeding channels is also
influenced by the driving depth of the bushings.
- Visually check the wear of the bushings: in the
coupling ends shown in the photo the bushing usu-
ally keeps the original look, check in the rest of the
bushing if there is evident removal of material. If
this occurs as stated, proceed to replace the
crankcase halves.
N.B.
SMALL MARKS AND SCRATCHES OF THE SHAFT ROTA-
TION ARE NORMAL SIGNS OF ENGINE USAGE, AND DO
NOT AFFECT THE CORRECT FUNCTIONING.
Measurement of crankcase halves - crankshaft coupling clearance
- The nominal diameters of the bushings, even if of the same coupling category, may differ by hun-
dredths due to the plastic slackening of the material of the crankcase due to the driving load.
- Measure along the axis of the «A» cylinder, using a bore meter at two depths indicated in the figure,
the diameter of the bushings.
- After measuring the two diameters, take the average.
Characteristic
«A»
AXIS CYLINDER
- The bushings housing hole in the crankcase half is divided into two categories depending on the size,
Category 1 and Category 2.
Specification
CAT 1
CAT 2
- Combine the shaft with two category 1 crankwebs with the category 1 crankcase (or cat. 2 with cat.
2). Furthermore a spare crankcase cannot be matched with a crankshaft with mixed categories. The
spare crankshaft has half-shafts of the same category.
- According to the classification of the shaft CAT.1 - CAT.2 combine a complete crankcase pre-fitted
with suitable bushings according to the starting shaft.
CRANKCASE HALVES
Cat. 1
Cat. 2
Cat. 1
Cat. 2
D
IAMETER OF CRANKCASE WITHOUT BUSHING
CATEGORIES
ENGINE HALF-SHAFT
Desc./Quantity
30.959 - 30.965 mm
30.953 - 30.959 mm
Cat. 1
Cat. 2
Cat. 2
Cat. 1
Technical Data
BUSHING
E
B
C
C
DT - 37