Honda G100K2 Applications Manual page 72

Minimum pulley diameter – belt type
Small pulley diameters increase the bending stress on the V-belt, have a limited contact area between belt and
pulley and therefore reduce the transmission efficiency and durability.
Minimum diameter pulleys should be avoided as much as possible.
•
For A-type belts used on engines of less than 5.0 HP, the minimum pulley outer diameter is 80 mm.
•
For A-type belts used on engines of 5.0 HP or more, the minimum pulley outer diameter is 90 mm.
•
For B-type belts used with all engines, the minimum pulley outer diameter is 120 mm.
Belt type
Belt width (mm)
Minimum pulley
diameter (mm)
DETERMINING LENGTH OF BELT
Belt length = 2L + Π (D + d) + (D –d)²
2
Belt number * = belt length (mm)
25.4
* round off fractions to next higher integer
M A
10 13
50 80 130
4L
B C
17 22
200
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POWER TRANSMISSION
D E
32 40
300 450