Project Aprilia SR50 more power!

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

By Mike Kojima

In order to honor the tragic passing of the owner of Segway, James Heselden in a freak accident on a Segway, we will dedicate this story which also promotes alternative transportation and modding in a sort of different way to his memory and vision.

Project Aprilia SR50 more power!
We replaced our Leo Vince pipe with the Tecnigas RSII which is optimized for a big bore larger displacement engine.  The Tecnigas has quality construction with a carbon Kevlar silencer.

We have brought our high tech Aprilia SR50 scooter from a fairly low powered urban runabout, whose direct injection stratified charge 50cc two stroke was designed as much for greenness as for performance, to a practical suburban commuter whose acceleration and 55 mph top speed are fast enough for serious riding in cut and thrust morning commuter traffic.

To read more about what we have done to Project SR50 read here!

Project Aprilia SR50 more power!
Project Aprilia SR50 more power!
To meet European standards for teen drivers,  our pipe came with these welded in restrictors.  There were two, one by the exhaust port, another by the silencer.  Of course we had to remove these for the pipe to actually work!  The Tecnigas RSII pipe has a venturi in the stinger section to help improve the powerband.  You can see the venturi section at the end of the tail cone here.

However we wanted a little more, we feel that to handle rush hour traffic a little more top speed is in order to avoid being run over by the rat race.  For safety someone on a scooter should take his position in a lane.  They should also be fast enough so cars will not tailgate.  To get to this point where our scooter would be able to fill most of the role of a motorcycle it needed a little more beans.

Project Aprilia SR50 more power!
The restrictors are removed by grinding out the spot welds with a die grinder.  You could use a dremel tool as well.  The restrictors are designed to be easily removable so this is not hard at all.  Just don't damage the sealing surfaces.

Our first step was to replace our Leo Vince exhaust with a Tecnigas RSII.  Although the Leo Vince is one of the best exhausts for the stock displacement, the Tecnigas RSII was designed around a big bore engine with a larger internal volume and more aggressive tuning.  With good quality construction and a carbon Kevlar silencer, the Tecnigas RSII looked very serious and ready to run.

Project Aprilia SR50 more power!
 Can you believe that the holes in the restrictors are this small!?


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Tuesday, September 28, 2010 4:32 AM
Love the scooter articles and I cant wait to find one that peaks my interest maybe I am being to picky but I am still looking and its coming to the time where I may put it on hold for the winter and save up extra cash to get a better scooter to start with.
Tuesday, September 28, 2010 5:39 AM
It's very refreshing to hear reports of modifications doing absolutely nothing or close to nothing when installed. I can't count how many times I've done engine or chassis mods and gained infinitesimal results. Yet until I did them, I was convinced they would help in some significant way. Now when I hear people report back great gains from seat-of-the-pants results from each and every little thing they do (that's I've done as well) I know there's a mountain of placebo going on.
It's nice to know the MotoIQ crowd aren't very susceptible to that bias either.
Tuesday, September 28, 2010 1:14 PM
@ BenFenner: It's true that the massive intake setup did nothing on page 3 but by the time we get to page 4 of the article they were able to realize large gains by coupling the additional flow it provided to the additional fuel allowed by the adjustable fuel pressure regulator (or at least that's how I see it).

I know you know all this but I figured it was just something worth making clear. I too like the fact that Mike and the rest of the guys here give us the straight goods when it comes to modifications/results.

Mike Kojima
Mike Kojimalink
Tuesday, September 28, 2010 1:56 PM
Also note that the only real data I was able to develop was top speed and time to distance because these scooters don't fit on any dyno we have access to. For RW powe,r variator tuning can affect the curve.
Tuesday, September 28, 2010 7:03 PM
LOL Mike love this photo:

NICE work, looks great :D
Saturday, January 22, 2011 7:54 AM
were do i get a Leo Vince pipe from for a Aprilia sr50 2006 ??????
Wednesday, February 26, 2014 1:49 PM
The problem when you switch the ecu from the one that was specifically designed for the Morini engine to the piggyback one is that you will not be getting the proper amount of oil injected into the engine. On a Piaggio engine (the one that piggyback unit was made for) you can manually set the oil pump to inject more oil. The morini engine has an electronic solenoid for an oil pump and the Malossi ecu adds extra pulses to the solenoid to compensate for the added displacement of a 70cc kit. With the piggyback unit on a Morini engine you are only getting the amount of oil a stock 50cc engine would get LOL.
Mike Kojima
Mike Kojimalink
Wednesday, February 26, 2014 5:10 PM
Haven't had a problem in hundreds of flat out miles.
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