Yamaha Vmax VMX12N, Supplementary Service Manual

Page: 364 / 405

V-BOOST SYSTEM
V-BOOST SYSTEM
Description
The V-Boost consists of a servomotor, a control
cable, special intake joints and butterfly valves.
The front and rear cylinders are connected by
the special intake joint. In the middle of the
intake joint
is the butterfly valve.
The butterfly valve is opened and closed by the
servomotor. And this valve
is securely closed
by means of i t s return spring.
The servomotor senses rpm from engine's
operation. The butterfly valve begins to open
a t
approximately
6,000
r/min and fully opens at
approximately
8,000
r/min.
For example, while the #1 cylinder is in the
intake stroke, the
#2
cylinder is in the com-
bustion storke and consequently the
#2
carb is
a t rest. If the butterfly valve opens in this state,
an air fuel mixture flows into the
#1
cylinder
through the #1 and
#2
carbs (as in the super-
charger system).
This results in an increased intake efficiency per
ignition signals and controls the butterfly valve
cylinder, leading
to
higher performance.
CYLINDER
COMBUSTION
C EXHAUST
D INTAKE
E COMPRESSION
0° 180° 360° 540° 720° 900°
180° ± 70'°
1 1 0 °
7-61