Mention four Strokes to most twostroke-
leaping, hardcore motoheads
and they would likely say, "I wouldn't
ride one of those pig bikes if you gave me
a contract better than McGrath's!"
Thumpers are too heavy and too slow, period,
end of discussion. Well, (that might
be the consumer response: if you can't
pull it out of the box and win with it, go
buy something elsc\e. At the other end of
the moto-spectrum, you have a guy like
Frenchman Thierry Karouby, who lives to
modify existing designs and materials until
an all-new beast is created. To serious
gearheads, a factory's finished product is
only a starting point, a blank canvas.
Karouby has modified XR600s and
DR350s in the past, and he chose the Husaberg
FC501 for Project Four-Stroke
Light because "it's the best four-s troke
enduro bike, even though it's not taken as
seriously as Japanese bikes." Even though
the Husaberg weighs the same as its
500cc two-stroke counterparts (235
pounds), Karouby wanted less, much less.
He set out to create a 200-pound fourstroke,
a big 500 that weighs less than a
125cc motocrosser!
PROJECT HUSABERG LIGHT
Like any works-bike builder, Karouby
started with a stock frame and stripped its
paint. He wanted more stability, so he
kicked the headset out a degree. Karouby
saved some 1.5 pounds by giving the
chassis a naval zinc coating instead of repainting.
Then he replaced the steel subframe
with one made of titanium. Karouby
checked out all of the aftermarket
handlebars, sprockets, chains and tires,
then picked the lightest ones. Smaller than
stock brake discs were chosen to fit
unpainted CR hubs, then the hubs were
laced to Excel rims. The spoke nipples
and axles are Ti, and a CR500R swingarm
replaced the hefty Husaberg piece. Linkages
were handmade and have Ti bolts.
The fork is a standard WP 4057, but the
triple clamps are billet aluminum and the
steering stem is Zycra, which is lighter
and stronger than "standard" aluminum.
On it went, with every part eyed for
weight savings. All bolts were replaced by
Ti fasteners. Replacing the stock plastic
with a combination of carbon-fiber and
Kevlar saved another 6.5 pounds. The
steel clutch push rod was also replaced
with Ti. Slight savings were made in the
head, as the ports were polished, but the
engine was left very much stock, because
Karouby likes the 501's performance and
powerband. He did go all out on the exhaust,
using Inconel, a space-age all oy,
and Formula 1 design to coax another 600
rpm out of the potent Husaberg motor.
WHAT A CONCEPT!
When Karouby went Jenny Craig on
the 501, it weighed 235 pounds. After one
year and $24,000, the 'Berg Lite tipped
the scales at 202, a weight savings of 33
pounds! That's about $485 per pound, so
that was some expensive pork, but you
definitely can't call this bike a pig.