1975 Norton Commando 850 Vibration-Free Isolastic Ride - Vintage Motorcycle Ad

Description

1975 Norton Commando 850 Vibration-Free Isolastic Ride - Vintage Motorcycle Ad
Original, Vintage Magazine Advertisement
Page Size: Approx. 8" x 11" (21 cm x 28 cm)
Condition: Good
The problem.
The big-bore vertical twin is an ideal supert
engine. Almost. It has tremendous
torque over a wide power range —
plus a low center of gravity and
a narrow profile that lets it sit deep
in the frame. This gives the bike
itself a doubly low center of
gravity, and results in the kind of
road handling that has made
Norton famous. But the
vertical twin has an impolite
habit. Vibration.
The solution.
Norton invented (and patented)
the Isolastic System of motorcycle
construction to cope with vibration.
The key to the system lies in the
design of the engine mounting devices
—like the front engine mount
illustrated. A wide cylindrical
housing is attached to the engine.
Through this runs a long steel tube thatf^T
bolts to the frame. Between tube and
housing are four rubber bustlings, the
outer two of a soft composition to
absorb the vibration, the inner two
somewhat smaller and harder, to prevent
extreme movements. The device is
capped at both ends to an overall tolerance
of .010”, thus limiting lateral (side-to-side)
movement. As a result, the Isolastic
engine mount restricts vibration to a
single vertical plane.
RThe result.
e Isolastic “single-
e” principle underlies
itire bike’s construction,
xe engine and drive
eluding swing arm and
PF rear wheel) are coupled together
into one unit. This sub-assembly
is then joined to the main frame by three Isolastic
mounts laid out in a triangle, one each at
the front, the rear, and the top. This triangulation
limits movement of the entire sub-assembly to a single
plane, the exact same plane as the track of the
bike. Thus the wheels always track true, so
the bike’s handling stays true. And
Norton alone combines race-bred road
handling with a super smooth ride.
Norton features —
electric starting, fixed-
caliper/dual piston disc
brakes front and rear, left
foot shift, Roadholder®
forks, Girling shocks,
dual Arnal 32 mm
concentric carburetors.
8639-7509-08 RL- 13904-AL-7509-02