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What is CAN-bus on a motorcycle? Tech explained
h e O B D ( o n - b o a r d
diagnostics) port on your
Tmotorcycle is just the tip of
the iceberg when it comes to the
complex world of CAN-bus data
signals.
What is CAN-bus?
CAN-bus is a messaging system
that enables all electronic devices
on a motorcycle to communicate
with each other. “CAN” stands for
Controller Area Network, while
“bus” refers to the wiring that
carries these signals. So why is it
becoming standard on so many
bikes? LHR Motorcycle Magazine
consulted the experts at Optimate
for insight.
Why Do Motorcycles Use CAN-
bus?
Historically, a motorcycle’s
electrical system began at the
battery, with each component
connected via a fuse box to ensure
safety. As motorcycles have grown
more complex and reliant on
e l e c t r o n i c c o m p o n e n t s ,
individually wiring each device
directly to the battery became
impractical. CAN-bus serves as a
centralized communication hub
b e t w e e n t h e b i k e ' s
(Electronic Control Unit) and its
various devices, allowing data to
flow through a single wiring loom.
Editorial sponsored by Twiggy the Weed Kid
This reduces the amount of wiring
needed, simplifying installation
and cutting costs. However, it can
complicate things for home
mechanics trying to trace wiring
i s s u e s . F o r e x a m p l e ,
disconnecting the tail light might
not yield the expected results, as
the system may power the
indicators instead if it doesn’t
recognize the bulb or LED.
W h i c h M o t o r c y c l e
Manufacturers Use CAN-bus?
Today, nearly all major Japanese
and European manufacturers
have adopted CAN-bus, with
Harley-Davidson recently joining
the trend. Ducati was the first to
implement it, using CAN-bus in its
999 superbike in 2002 for
communication between the ECU,
immobilizer, and dashboard. BMW
followed with a full CAN-bus
network starting in 2004 with the
GS range.
Benefits of CAN-bus for Riders
The CAN-bus system allows for a
variety of safety, efficiency, and
convenience features to be
integrated through software, rather
than needing complex wiring. This
E C U means more functionality at a
lower cost. It also simplifies fault-
finding; any issues can trigger a
fault code displayed on the
dashboard, making it easier for
users or mechanics to identify
problems without tracing through a
tangle of wires and fuses.
Disadvantages of CAN-bus
One drawback of the CAN-bus
system is that it often has a built-in
limit for power draw or resistance
from connected components. If
y o u t r y t o a d d e l e c t r i c a l
accessories, such as brighter
bulbs or heated grips, the system
might interpret this as a fault and
shut down the circuit. For added
safety, it’s usually best to wire
accessories directly to the battery.
When integrating with a CAN-bus
system, caution is necessary. For
instance, tapping into the main-
beam circuit of a KTM 1050
Adventure for a spotlight might
seem logical, but that wire also
transmits crucial sensor data,
potentially causing interference.
Some accessories require signals
from existing components to
function correctly, so it’s essential
to verify compatibility with the
manufacturer.
Charging a CAN-bus Equipped
Motorcycle
Maintaining the battery is crucial
for the smooth operation of a CAN-
bus system, as a dead battery can
lead to significant issues requiring
professional resets. While
m a n u f a c t u r e r s t y p i c a l l y
recommend charging the battery
while disconnected, it’s usually
safe to charge a CAN-bus
motorcycle with a quality charger
using crocodile clips or a fly-lead.
Charging can also be simplified.
For example, the OptiMate 4 CAN-
bus edition charger is designed for
use with CAN-bus bikes, allowing
for automatic activation without
needing to turn on the ignition.
Always check compatibility before
using any charger to ensure it can
operate safely without manual
intervention.
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