Project Cars

Project Aprilia SR50 more power!

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

By Mike Kojima

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.


Project Aprilia SR50

100 MPG Madness, Project Aprilia SR50- Brakes, Bling and Suspension

By Mike Kojima

In the last edition of Project Aprillia SR50, we had upgraded our little 50cc high tech scooter from an in-town runabout to a serious 60 mph capable commuter capable of handling rides on the fastest crowded main streets and parkways without cowering in the slow lane. Now to build a balanced bike, since we upped the speed and acceleration, it was time to address the brakes and suspension.  The SR50 is blessed with some excellent Grimeca hydraulic disc brakes from the factory but we set out to improve them.

To see the other segments of this project click here!


Aprillia SR50 Dr Pulley racing clutch

100 MPG Madness, Project Aprilia SR50- Modding the driveline

By Jeff Naeyaert

In our last installment, we had greatly improved the power of our Aprilia SR50 by installing a Malossi big bore kit ported by AF1.  The big bore kit brought our displacement up to 68cc and improved our acceleration by a bunch.  However our top speed didn’t change a whole lot, despite our gains in hp and torque as our redline was only increased by a few hundred rpm.  Our top speed was a disappointing 55-56 mph and we were hoping to see 60.  We were also annoyed by a distracting check engine light on our digital dash due to compatibility issues between the Malossi ECU designed for Euro versions of this scooter and our USA spec dash.

To read more about our project click here!


MotoIQ Project Aprilia SR50

Project Aprilia SR50: 100 MPG Madness Part 2, Engine Internals

By Mike Kojima

In our last edition of Project SR50, we had reached the limits of simple bolt on modifications which left us with a nicely running Scooter, capable of just over 50 mph with acceleration good enough to keep up with traffic and 115 mpg. With more time, we are really taking a liking to the refined Aprilia SR50, which rides, handles and brakes better than any scooter in this displacement category. We also like its sporty looks. The SR50 is the king of urban commuter scooters and we are going to take it to the next level.

See Part 1 Here!


Project Aprilia SR50: 100 mpg Madness Part 1, Basic Bolt on Stuff

By Mike Kojima

Our new two wheel project is a very unique machine; it is an Aprilia SR50, perhaps the highest tech scooter on the market. It uses a full of tech, Orbital engine to combine the compactness and power of a two stroke engine with the fuel economy and low emissions of a tiny four stroke. The Aprilia engine uses licensed Orbital technology which is basically An ECU controlled, directly injected, stratified charge two stroke. Two strokes by nature produce pretty low NOX emissions due to their low operating cylinder pressures but are terrible for hydrocarbons as they tend to blow raw fuel out the exhaust port on overlap.


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