1965 Canadian Dragster to Challenge British - 2-Page Vintage Motorcycle Article

Description

1965 Canadian Dragster to Challenge British - 2-Page Vintage Motorcycle Article
Original, Vintage Magazine article
Page Size: Approx. 8" x 11" (21 cm x 28 cm) each page
Condition: Good
Richard Forest of Montreal, Canada
calls his machine “the fastest motorcycle
dragster in Canada." We are not in a posi-
tion to prove or disprove that statement,
but it seems entirely possible that it may
be correct, for the “Bentley’s Spl" cer-
tainly has what it takes to burn up any
dragstrip.
Sponsored by Bentley’s Cycle & Sports,
large Montreal BSA dealer, the dragster
is, naturally, powered by a pair of potent
BSA twin engines. Three years of effort
and nearly 00 have been spent to date
on the bike. The result? % mile speeds
of 140mph-plus with elapsed times in the
low ten second bracket! Like most motor-
cyclists and hot rodders, the Bentley crew
is never satisfied, and is constantly mak-
ing improvements and alterations that
will quite probably result in even better
performance at the International Drag
Festival in England later this year.
J 2.5 TO 1 PISTONS
Following the universally accepted
speed law “low weight, high power,” For-
est began by squeezing every possible
horsepower from both BSA twins. Cylin-
ders are bored .060" over the standard
650cc bore. Pistons are special 12x/2 to 1
compression made by MC Supply of Los
Angeles. Piston rings are Grant. In the
cam department, Forest consulted one of
North America’s leading motorcycle cam
experts, Ravesi Racing Cams of Massa-
chusetts, who designed some really hot
ones for the dragster, with a lift of .475"
according to Forest, who claims that the
engines will turn rpm's in excess of 9,000
with the special Ravesi valve springs.
Push rods are by Webco, while the valves
themselves are BSA stock oversize.
Rocker arms are all drilled for lightness
and highly polished. All timing gears are
drilled to remove excess rotating weight.
Along the same lines, two pounds of
metal have been shaved from the fly-
wheels and both engines have been com-
pletely balanced on a special machine
using a stroboscopic light. The balance
factor now stands at 73% of the recipro-
cating weight.
Currently the fuef being burned is 10%
nitro and 90% alcohol which is fed
through two Amal 1%" carbs. Forest
claims that a conversion to gasoline
would be easily accomplished.
Intake ports have been opened to 1%
and then highly polished. Champion
sparkplugs, No. N-63R are employed.
Power is transmitted through a Barnett
alloy clutch into a special two-speed
gearbox, a converted BSA unit with first
and third gears removed.
LIGHT RIDER
Extensive use of light alloy and alumi-
num parts keeps total weight down to 347
lbs. Almost everything except the frame
(steel) is made of magnesium or alumi-
num. The following are aluminum: wheels,
fuel tank, oil tank (located between the
engines, capacity: 1 quart), chain guard,
seat, front hub, and brake drum assem-
bly. Magnesium parts include all engine
and transmission brackets. An important
bonus in keeping total weight to a mini-
mum is the fact that the rider (Andre De-
nault) weighs in at only 120 lbs. Too
often, rider weight is not considered ade-
quately in competition motorcycle build-
ing. Even in the automotive field, many
times a builder will spend hours upon
hours trimming off 3 or 4 pounds, only
to let a 2501b. or 3001b. driver take the
wheel.
A recent addition not shown in these
photos is a new rear wheel. It’s an 18"
alloy rim laced to a Gold Star hub and
utilizing an Avon 4.00" x 18" drag slick.
Readers letters and personal experi-
ence tell us that motorcycle drag racing
is truly “big time” in Canada, and es-
pecially in Napierville at the fine % mile
strip. On a warm afternoon there spec-
tators can expect to be treated to a hot
speed show with a variety of machines
ranging from Vincent Black Lightnings to
Harley-Davidson XLR’s, full house Tri-
umphs and BSA’s. One BSA (single en-
gine) Rocket has turned 115mph. There’s
also a moving dual-engine Norton drag-
ster that may be seen in a future issue of
CYCLE. But in spite of the large number
of “hot ones” at Napierville, there is al-
ways a tense lull of anticipation when
“Bentley’s Spl.” is on the line.
13835-AL-6504-04<