Project Honda Ruckus Part 7: Building the Engine


Honda Ruckus big bore wpc treated
Our block was bored 3mm oversize for the forged Chanito piston and WPC treated for low friction and longer life.

In the rest of the engine, WPC was used on the cylinder bore, the piston including the pin bores, ring grooves, entire piston surface, rings and piston pin.  We also WPC treated the entire gear train.  We used the gears from a Honda Metropolitan scooter as they are higher in ratio than the Kitaco gears used in our first go around.  Every gear in the gearbox was WPC treated to reduce friction.  Our Polini variator was WPC treated to make it more sensitive and make the belt surface more wear resistant.  Nearly every moving part was subjected to WPC treatment in our engine.  We are hoping that this might gain us as much as 1/2 hp including friction reduction in the transmission.

WPC treated honda ruckus metropolitan gears and polini variator
For our new motor we used the gears from a Honda Metropolitan scooter as it has a higher gear ratio than the Kitaco gear set we had used with our previous engine.  We WPC treated all of the gears to reduce our friction levels as low as possible.  You can see the silky luster of the WPC treatment.  We WPC treated our variator to make it more sensitive to speed variations and to improve its face wear against the belt.

For our carburetor we are going to use a Keihin PE20 which is slightly larger than the PC20 we used on our previous engine.  We also fully ported the intake manifold and enlarged the junction between the intake manifold and the intake port.

Chanito Motors forged big bore piston
To get an idea of how small our Chanito Motors forged big bore piston is, check out the size of the quarter!  The lustrous look is due to the WPC treatment.

For the engine's bottom end we once again used Chanito Motors 3mm oversize flat top tough forged piston.  Chanito's high strength head bolts and thin head gasket were used again as well.  The stock crank was also used.


  1. Hello there. I’m trying to replicate your 58.1cc ruckus project. How has it lasted since completion? Is it still running well? Any issues?

    1. In other words, its not a daily driver, and just a show piece. If you want speed on your 50cc, sell it, and get a bigger bike/motor, and don’t sacrifice the reliability.

      1. It is perfectly reliable. I rode it a lot, I just lost interest in it because our shop moved to where the drivers suck and I had to ride through some rough neighborhoods to get there so I didn’t feel safe riding it to and from work anymore. This made me lose interest in scooters.

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