UNLEASH THE BEAST - 50cc DE-RESTRICTION
IMPORTANT: First important thing to note before de-restricting,
is that you MUST check that you're legal, i.e. you have the appropriate licence.
And if you are to undertake de-restricting your
Dragster yourself in doing so you will invalidate your bike's warranty. The
following guide is for information purposes only and it is advised that
de-restrictions are carried out by an authorised Italjet dealer
Standard 50cc Dragsters are capable of around 35mph on average, after
de-restricting expect to get something like a 10-15mph increase making
this is one of the cheapest and most effective engine modifications
for a 50cc Dragster.
Partial de-restriction. If you purchased your
Dragster in the UK or any other country apart from Italy or Spain
ignore this stage as this de-restriction will most
certainly have already been done for you. UK Dealers normally
do this de-restriction when they undertake what is known as a
PDI (Pre-Delivery Inspection) before handing the bike over to
the owner. Basically a washer or restrictor cone is removed from
inside the exhaust down-pipe. With a restrictor cone fitted a
50cc Dragster is capable of a mere 24mph, Italian and Spanish
laws dictate that this kind of restriction is necessary for teenagers
to be able to ride as young as 14 years of age. Basically, the shape of the cone
reduces the exhaust 'inlet' to around 1cm which restricts waist gases from escaping, with the
cone removed an increase in gas flow is enabled allowing the engine
to breath more easily. To remove the cone you would have to cut through the
welding which holds it in place using a Dremel tool for instance.
1: Remove exhaust restrictor. This involves the removal
of a closed-off restrictor pipe (or resonator tube) which
protrudes from the side of the down-pipe (as seen in pic 2 and 3).
After un-bolting the down-pipe (pic 3), the next stage is to either cut the restrictor off
(pic 4) and re-weld the hole, or squash the pipe together in a vice as close to the
downpipe as possible. Removing the restrictor pipe altogether
and re-welding is the recommended option as squashing the pipe
will fatigue the metal making it more prone to cracking which
will allow gases to leak and in the end won't do your engine any
5: With the exhaust restrictor now removed the hole on the down-pipe now needs
to be re-welded.
6: Remove pulley spacer. The next stage of de-restriction involves the removal
of what is known as a 'pulley spacer' or 'variator bush' as it
is sometimes called (the terminology often varies).
To locate this restrictor you will need to remove the transmission casing by
unscrewing all the bolts.
Inside the case (pic 7), look between the two halves of the front pulley
(variator) to see if there is a spacer. If there is, this
is what you need to remove. What this spacer has been doing
is limiting the gearing to a low speed ratio which prevents the
bike from reaching 'top gear'.
Undo the center nut from the variator (pic 8), here we used a 17mm air gun, although you
could also use a socket tool. Pay attention to the order in which the parts
are removed so that you can put them back in reverse order.
Now remove the spacer (pic 9), it's a coincidence that the spacer also
happens to resemble a wedding ring. Technically what's happening is the front
and rear pulleys both slide in and out varying the position at which
the variator belt runs between them. The spacer physically prevented
the pulleys from coming fully together therefore limiting the highest
With the pulley spacer now removed, re-assemble the variator in reverse order (pic 10).
Re-fit the transmission case, bolt the exhaust back on securely and check all fasteners,
go for a test ride.