(Far left) Marc
surveys the lines
of his custom
subframe and seat
unit. (Left) Late
workshop nights
and early mornings
are part of the
course if you're
trying to make it
as a custom-
bike builder.
I am going to outsource that
to someone who specializes in
mold making and carbon fiber
stuff. So, then I can effectively
reproduce the whole build and
it's a much quicker process."
Bell's Thunderbolt design uses
the stock XSR900 cast alumi
-
num frame and swingarm with
a custom subframe for his seat
unit that has hues of Colin Ed-
wards' factory Yamaha YZF750
racer from 1995-1997 to it.
"I had to make all the fairing
brackets, and the fuel cell has
been a bit tricky," Bell says. "It's
the first time I've made a fuel
cell, and you need to put a bit
of tank sealer in, because you
normally get little, tiny holes in
them. The stock tank is huge. It
goes out really wide to get the
required capacity for road use.
At the moment, the fuel cell is
enough for the track use and
what I want to do, but if I do a
road version, I might extend the
fuel cell down into the seat unit
to match the capacity of the
stock tank."
The UK bike industry is one
of the most robust in the world,
and Bell's leaned on some
friends to get Thunderbolt on
the road, with British suspen
-
sion gurus Maxton providing
the fork internals and their
GP10 rear shock, HEL providing
the V2 front and rear calipers,
master cylinder and braided
brake lines, and Dymag provid
-
ing their UPX7 forged alumi-
has been around for centuries,
so there's a real craft to it. It's
also quite a clean process. If
you make a panel and then you
bolt it onto the bike, you've got
your finished panel already. You
don't have to make molds and
then use lots of resin and lay
up carbon fiber or fiberglass.
People have a lot of respect for
this build because it's metal, not
fiberglass or carbon. But for me,
it's a skill I have now. If I need to
make something for the bike, I
can get on with it, and it's done.
That's satisfying."
Bell notes also that there's
not a huge weight difference
between his 1.2mm aluminum
bodywork and a similar design
made from fiberglass. Carbon fi
-
ber is a different step entirely and
requires retooling, but Bell says
now the original design has been
completed in aluminum, creating
customer kits out of fiberglass or
carbon is no problem.
"Fiberglass isn't particularly
light when you've got all the
resin in it," Bell says. "Now I've
got this all figured out, the plan
is to take molds from it and then
have it produced in carbon fiber.
VOLUME ISSUE SEPTEMBER , P113
