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De-restricting an Aprilia Scooter (Or Most Any Modern Scooter)

If you drive a modern automatic (twist-n-go) scooter, then it is likely that your scooter has been restricted to prevent it from reaching its full power. This is typically done to keep the power and speed down so that the vehicle can be registered under scooter or moped classifications that many states have. This classification means many scooter drivers do not need license plates, special licenses, or expensive registrations.

However, how much fun is it to have a restricted vehicle? Not much. So if you'd like to get the full power out of your ride, you can remove the restrictions yourself, and enjoy a vehicle operating at its full potential.

This article deals with derestricting a 2004 Aprilia Mojito 50 (known as the Habana in Europe) and mentions specific differences with the technique for the Aprilia SR50 DiTech, since these two scooters share the same drivetrain. However, the derestriction techniques described here work on most modern automatic scooters, with some variation between brands and models. This document was originally written as a thread on the ApriliaForum by Scott and all credit should go to him. He wrote the bulk of the document, and took the pictures. I am simply removing the info from the forum context, doing some editing for clarity and formatting, and putting it up for all to see (specifically Googlers).

How to de-restrict a scooter is one of the most common questions asked on the ApriliaForum and in emails to myself and others. Hopefully this article will give you what you need to get into that scooter, and de-restrict it.

Let me start by letting you know some basics...

  • If you tamper with the motor in any way to de-restrict it, some dealers will completely void your warranty. So make sure this is a sacrifice you are willing to make. If you mess up your scooter while wrenching it in your back yard, your dealer will help you out, but don't expect too much sympathy.
  • De-restricting your scooter may cause it to violate your State or Country's laws concerning the scooter or moped classification. For instance, in Missouri, if your scooter makes over 3 horsepower or goes over 30MPH, then it needs to be registered as a motorcycle, and the operator needs to have a current motorcycle endorsement on their license. Many people don't bother to do this, since the vehicle still looks the same as it did, and enforcement is very rare, but you should be aware of your local laws, and you must accept responsibility for your actions if you decide to break any of them!
  • ALL bolts and socket head cap screws are in metric! Don't try to work on your vehicle if you don't have metric tools, you will just end up messing up the heads.
  • This article describes the technique for a 2004 Aprilia Mojito. Much of the drive-train is the same on the Aprilia SR50 DiTech, and is very similar on the other Aprilia models. If you have another model than the one described here, just go slow, and make sure to note differences between your setup and this one.
  • If your scooter is not an Aprilia, then this guide may still be of use. The Mojito uses the Morini engine, which means it shares many parts with other vehicles using the Morini, such as Suzuki Katana scooters. Also, while the engines are fairly different, most Minarelli engine scooters have a very similar setup in terms of restriction. This includes many Yamaha's and Malaguti's. Even Piaggio's and modern Vespa's have similar restrictions.

The Mojito has 4 restrictions on it. They include:

  1. A small washer in the variator.
  2. A jet restrictor in the carb.
  3. Two restrictors on the exhaust system, an inner flange restricting flow, and a resonator tube that impedes scavenging.

Most modern scooters have some combination (or all) of the above restrictions. To properly de-restrict a scooter, you must do all of the parts. If you only do half the job, you could actually damage the scooter. Ask your dealer, or other enthusiasts who own the same scooter as you, to find out exactly where your model is restricted.

The SR50 DiTech has only two restrictions, but one of them is different from most scooters. The washer in the variator is present (though it may not be on the '03 DiTechs I have heard?), but it also has a restriction in the ECU, the computer that controls the fuel injection. This restriction MUST be removed by a dealer, since only they have the equipment to reprogram the ECU. The equipment takes the form of a Gameboy cartridge that plugs into your scooter and into the Gameboy, giving the dealer the ability to update your software. Many dealers will do this for free, some may charge for the labor (should only take a few minutes, really). The exhaust isn't restricted per-say, but it should be replaced for best performance, along with installing lighter roller weights. Of course, that costs a bit of money.

Results for de-restricting these vehicles are as follows:

  • Scott's SR50 DiTech - Stock had decent acceleration, and a top speed of 40-45 MPH. After de-restricting (washer removal and re-mapping), I had a top end of 58 MPH, but had terrible acceleration, and a dead spot from 35-45 MPH. I put a Gianelli exhaust on, and a new Malossi Fly clutch. I used the 6.5 gram roller weights that came with the pipe, and I get 60MPH on level ground with great acceleration and no dead spot.
  • Sam's SR50 DiTech - After de-restriction, and the fitting of a Gianelli NRX exhaust and a Malossi Fly clutch, top speed is about 60MPH on level surface, with consistent acceleration through the entire range. After having troubles with a dead spot that surfaced at around 35-40MPH, I lightened the weights from 6.5g to 6.0g and installed a new White contra spring, which removed the dead spot and returned acceleration to its prime. Basically identical results to those found by Scott.
  • Scott's Mojito - Stock... Well it was a DOG!!! 30 MPH, 35 MPH downhill, with virtually no acceleration. After completing all 4 de-restrictions, a top speed of 47 MPH (verified), and really good acceleration... Everything else is still stock! The only thing I bought for it was a .8 mm jet ($10)!!! I have an Arrow Classic high performance exhaust for the Mojito also, but I recommend getting the Leo Vince pipe instead. With that on, I have even better acceleration, and a top end of about 52MPH flat out, and 55MPH down hill!!!

Just a few notes about working on your vehicle: Remember where every hose and cable you disconnect goes! This is very important. You might think you can remember each little screw and hose, but when it comes time to reassemble, its very easy to mistake a few hoses or screws and cause yourself a world of hurt. Do what I do. Make little drawings of everything as you go, and use little labels on pieces of tape to identify hoses and mark their locations. It sounds silly, but it will save you a lot of trouble, trust me!

Also, keep in mind that Scott and I are not mechanics, just interested scooter fanatics. When in doubt, take it to your dealer! However, now that all this prep work has been laid down, lets get into the de-restriction.

 

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