CASE STUDY: PROJECT DRAGSTER
The Dragster looks like no other scooter in the world. The Dragster
is engineered around an open trellis frame similar to its Italian
big brother, Ducati. Italjet's patented Independent Steering System
(SIS), with a horizontal hydro-pneumatic shock that rides between
your legs is truly a work of art. The front swing arm rotates
through a very small arc, thus allowing the wheelbase to remain
almost constant when cornering. Because of the (SIS) system, mounting
points for the front and rear swing arms is very short which allowed
Italjet to make a chassis that is very rigid.
forces from the handlebars are transferred to the front wheel
through lightweight articulated rods that pivot on the front swing
arm. The advantage of the (SIS) systems vs. classic scooter type
trailing link or motorcycle telescopic forks is obvious from the
second you ride it; there is virtually no front end dive when
you're hard on the brakes. This makes it possible to trailbrake
the Dragster mid-corner without upsetting the scooter or affecting
your desired line. The Dragster's rear suspension consists of
a three piece alloy swing arm and transmission case that pivots
on a centrally mounted hydraulic monoshock. Very cool!! This state
of the art suspension and very low center of gravity, along with
fat Michelin tires and lightweight five spoke alloy wheels, allows
the Dragster to handle like no other scooter. Italjet also dropped
the handlebars in order to shift the riders position and weight
over the front wheel for increased traction in the twisties.
Dragster's brakes consist of a 175mm hydraulic front vented disk
and a 190mm hydraulic rear vented disk coupled with steel braided
brake lines and a weight of only 85kg. This combines to make stopping
the Dragster an eye popping experience!
Other cool items on the Dragster are: electric and kick starters,
automatic choke, CDI electronic ignition, under the seat storage,
race-style gas filler, chromed dash with white faced speedo and
a vast array of warning lights. One even gets a lockable storage
compartment for a cell phone!
You would assume by the name and looks of this scooter that it
was a 150cc to 200cc scooter. Some are amazed (and some even disappointed)
when they find out that it is only 50cc! In Europe, there are
bigger versions available, but there is rumour that we may see
a 180cc four stroke version here next year. Nevertheless we still
prefer the two stroke, even if it is smaller.
When these scooters come into the U.S. their motors are very
restricted. Fortunately, without spending a dime you can almost
double the speed of a stock Dragster by removing these restrictors
(there are two restrictors located in the exhaust system and one in
the variator assembly). With the restrictors removed, top speed
is 40-50 mph, so don't be fooled by the little 50cc liquid cooled
Minarelli engine. This is the same Minarelli motor used in other
high performance scooters in Europe, including the new Aprilia
'Area 51' & SR Replica scooters.
While these speeds might be fine for most, NOT FOR US! Our project
started by replacing the stock 50cc cylinder with a 70cc Malossi
M.H.R. (Malossi Hyper Racing) aluminium racing cylinder. The cylinders
were originally designed specially for the 1995 International Scooter
Trophy Cup Race in Europe. The cylinders are engineered for maximum
performance. While, at the same time, assuring extremely long
life. The compression ratio is 13.8:1 with a torque value of 7.35
N.m (.75Kgm). The stock metal reeds were replaced with Malossi
carbon fibre reeds for faster throttle response. A Malossi kevlar
reinforced drive belt was then installed for strength and smoother
acceleration. The stock 12mm Dellorto carburettor was replaced
with a 22mm hi-performance version, while retaining the stock
automatic choke and throttle assembly.
Because of the increase in power and torque, the stock variator
cannot allow the Dragster's transmission to engage within the
peak powerband. So, we installed a Malossi multivar adjustable
variator and played with the different weights until the desired
powerband was achieved. Getting the correct weight combination,
however, depends on the modifications being done, powerband desired,
and riding style. We also found that the use of the Malossi
torque driver greatly improved the scooters powerband. Its function
is to determine the precise moment when to engage. It has been
designed to give the Dragster maximum possible acceleration according
to the specific size of each motor. The special shape of the Malossi
torque driver was designed to keep the RPMs fixed at the point
of maximum power. The use of the torque driver allowed us to fully
exploit the modifications we made to our Dragster while still
maintaining very gradual and fluid delivery of torque to the rear
With our intake and transmission modifications complete, we turned
to the exhaust system. While the stock exhaust may look cool,
it's very heavy and does not take advantage of the engine modifications.
As the importer for Arrow exhaust systems, it was my obvious
choice for our project. The Arrow 'Limited Series' chamber
is hand made just for this Minarelli engine with 70cc cylinders
installed. This pipe is a work-of-art in itself, from its hand
braised welds to its carbon fibre/kevlar silencers, to complete
protection with a special glossy clear coat. Arrow also
make the 'Kompress Series' for stock Dragsters. We picked up
over 14 mph with the exhaust chamber. Is it noisy? YOU BET, but
it sounds great!!! Power is very smooth and linear. Our motor
setup pulls hard up to about 35 mph, then tapers off until it
hits 50 mph, then pulls hard again to 65 mph.
Our Dragster cruises great at 65 mph, with a top speed of about
80 mph. While our total investment is around $1000 (parts only,
labour not included), it does not have to stop there. There are
still several performance upgrades that can still be added, such
as: racing drive shafts, driving gears, secondary gears, gas charged
shocks, electronic power units, and adjustable clutches. Malossi
has recalculated the transmission ratio gears in super strong
hardened, tempered, molybdenum chrome steel. These straight cut
gears are interchangeable with the originals. The shaved straight
cut tooth gives maximum power transmission, it also reduces vibration
and saves a significant amount of energy. We estimate top speed
somewhere around 90 mph with all modifications installed. Stay
For the most part we found these kits to be 'bolt-on', although
we did have to swap some parts, adapt others, tweak some and even
grind another. With the right tools and good mechanical skills,
the kits take about 5-7 hours to install.
Our project Dragster now shows 965 miles and has had no problems;
it averages 80 mpg, costs about $8 a month to insure, and looks
'out of this world'. Wanna Drag?
Words & Pictures: Kregg Williams.
reprinted from Scoot Quarterly.
Thanks also to California SpeedSports and Mike K.