User Guide

67
E
7
6
6
8
2
1
5
1
3
4
Engine
Twin cylinder, four-stroke, 90° “L” type, longitudinal.
Bore:
94 mm
Stroke:
66 mm
Total displacement:
916 c.c.
Compression ratio:
1:11.0±0.5
Max. power at crankshaft (95/1/CE):
78.6 kW – 107 HP at 9500 rpm
Max torque at crankshaft (95/1/CE):
84 Nm at 7250 rpm
Max. rotation speed
10,000 rpm
Important
Do not exceed specified rotation speed limits under
any running condition.
fig. 51
ST4
Timing system
Desmodromic (type) with four valves per cylinder,
operated by eight rockers (4 opening rockers and 4
closing rockers) and an overhead camshaft. It is operated
by the crankshaft through spur gears, belt rollers and
toothed belts.
Desmodromic timing system (fig. 50)
1) Opening (or upper) rocker.
2) Opening rocker shim.
3) Split rings.
4) Closing (or lower) rocker shim.
5) Return spring for lower rocker.
6) Closing (or lower) rocker.
7) Camshaft.
8) Valve.