1965 Norton 750 Supercharged - 4-Page Vintage Motorcycle Article

Description

1965 Norton 750 Supercharged - 4-Page Vintage Motorcycle Article
Original, vintage magazine article
Page Size: Approx. 8" x 11" (21 cm x 28 cm) each page
Condition: Good
750cc Norton Street Bike Gets
Boost From Judson VW Blower
■ When Phillip Watterberg decided to
supercharge his 1964 Norton Atlas 750cc
Scrambler, he had three objectives in
mind. He wanted: (1) A machine that
would, in full street trim, turn upwards
of 120 mph in the % mile with e.t.’s
in the mid-eleven second bracket. (2) A
bike that would cruise effortlessly at 70
mph with an engine speed not above
3000 rpm, with proper gearing, for an
ultra-smooth highway ride. (3) A depend-
able, docile street cycle for everyday
transportation.
Phillip, an 18-year-old high school grad-
uate who plans to study mechanical en-
gineering, found the key to his desires
in the form of a Judson supercharger
originally intended for a Volkswagen! The
nature of the VW version of this popular
small car supercharger made it ideal for
the motorcycle application; Its compact
size (6" x 9") permitted an easier, less
bulky installation than some other pos-
sible choices, and being of the vane type
it operates only in proportion to throttle
opening and engine load. This eliminates
any tendency to overheat. Any time less
than y3 throttle is employed, the pres-
sure is kept on the vacuum side of the
scale, resulting in more normal aspiration.
But when the rider “grabs a handful of
throttle”, the pressure gauge needle
bounces past the 5 lb. mark (pressure in
the buffer chamber) to really force that
fuel-air mixture down the Norton’s throat.
REVERSED ROTOR
The supercharger was in the planning
and wishing stage for about five months.
But the actual purchase of the unit last
December got the ball rolling. The next
step was to order a specially built re-
versed rotor from the Judson factory,
since the Volkswagen and Norton crank-
shafts turn in opposite directions. Then
a buffer chamber had to be constructed
allowing more than 90 cubic inches of
volume while keeping to minimal exterior
dimensions. The design finally employed
allows access to the rear rockers and
ample space for the supercharger. Most
important in the design of the buffer
chamber are the two blow-off valves, one
on each side. Much experimentation and
trial went into the welding of this cham-
ber by expert welder Werner Kuhn. In...
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