Buell 2006LIGHTNING MODELS, Service Manual

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2006 Buell Lightning: Electrical 7-19
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INTERACTIVE EXHAUST SYSTEM (XB12 MODELS) 7.6
GENERAL
NOTE
The interactive exhaust system is standard equipment on the
XB12 models only.
See Figure 7-21. An electronically controlled actuator opens
or closes a butterfly valve (1) that controls exhaust flow in a
multi-chamber muffler.
The ECM monitors engine speed and throttle position while
alternating flow paths between the chambers to adjust back-
pressure optimizing torque and horsepower for the riding con-
dition.
For example:
1. At low RPM with a wide-open throttle, the valve (1) is
opened to reduce back-pressure so the engine can gain
RPM quickly. The exhaust enters (2) the muffler and
flows (3) through the open valve (1) into chamber C (7)
and then exits (8).
2. In the mid-range, the valve is closed to increase acceler-
ation torque. The exhaust flows (4) through chamber A,
around to chamber B and then through chamber C and
exits.
3. At high RPM, the valve opens again to maximize horse-
power. The exhaust enters (2) the muffler and flows (3)
through the open valve (1) into chamber C (7) and then
exits (8).
Figure 7-21. Interactive Exhaust System Muffler
1
2
3
4
4
7
3
4
6
8
10568
5
4
1
4
1. Butterfly valve
2. Exhaust in
3. Valve open (exhaust flow - chamber C)
4. Valve closed (exhaust flow - chamber A to B to C)
5. Chamber A
6. Chamber B
7. Chamber C
8. Exhaust exit