100 MPG Madness, Project Aprilia SR50 Part 5- More Power!


 Project Aprilia SR50 more power!
When compared to the Leo Vince on top, the Tecnigas RSII below has a larger and shorter head pipe and more volume in the expansion chamber.  This is to make up for the larger cylinder volume of the big bore engine.

We first had to derestrict our exhaust.  In Europe many of these small scooters are meant to be driven by teenagers with restricted licenses and scooters are intentionally designed with restrictions to limit their legal speed.  A lot of aftermarket exhaust systems also have restrictors so teenagers can rock a custom exhaust legally.  We had to remove our exhaust system’s two restrictors which took a few minutes with a die grinder to be ready to rock.

 Project Aprilia SR50 more power!
 The Tecnigas RSII is a sweet looking as well as performing pipe.

At this time we also changed our engine management.  Our replacement Malossi ECU worked fine except that it did not get along with our USA spec digital dash where it was causing a continuous check engine light and error codes.  The Mallosi ECU also did not have a barro sensor like the stock ECU and thus, the scooter seemed to be a little inconsistent power wise, running noticeably better on some days than others.

 Project Aprilia SR50 more power!
 We originally used this Malossi ECU for our kit.  It worked fine but it was not compatible with our US spec digital dash.  It also lacked the baro sensor of the stock ECU and could not compensate for differences in air density.  The ECU made our check engine light come on and gave false error codes.

We solved this problem by installing a piggyback Malossi ECU from a late model Piaggio scooter.  The piggyback plugs into the stock wire harness and uses the stock ECU.  Unlike a car, the Aprilia’s fuel injection system does not have self learning so this sort of signal management to get more fuel and alter timing is perfectly acceptable. The Piggyback ECU totally eliminated the digital dash check engine light issues and the engine ran more consistently from day to day. With these mods the engine really woke up with the top speed rising to 60 mph with better acceleration to boot.

 Project Aprilia SR50 more power!
 We replaced the ECU with this Malossi piggyback unit that works in conjunction with the stock ECU.  Goodbye error codes and welcome consistent operation due to having a baro sensor.



  1. Bonjour
    Pouvez vous me donner le branchement des durites du régulateur de pression essence et l’affectation de chaque durites s’il vous plait je suis en france et j’ai pas ce type de pieces toutes faites
    Can you please give me the connection of the fuel pressure regulator and the assignment of each hoses
    Thank you , l’m in France

    1. The regulator goes inline between the fuel pump and the injector. You need to take the higher pressure reference for the regulator off of the top of the air injector.

  2. Hello, I also want to install the larger throttle valve (26mm) on my Gilera Runner Purejet. However, I can’t find these anymore. Are these still available to buy somewhere or do you still have one? Kind regards from Germany Victor

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