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We did this in several ways. First we disassembled our Polini variator and sent it to WPC for treatment. The WPC treatment reduced the operational friction on the shaft and rollers which helped the variator be more responsive to changes in load. The WPC also helped the drive belt grip better and helped the belt face resist wear and grooving, factors that also hampers variator operation.
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| We WPC treated the variator pulley faces for Project Ruckus to help the aluminum resist wear and to help the belt grip better. The treatment gives the pulley faces a smooth, creamy textured look. |
Next we changed contra springs. The contra spring controls the tension on the drive belt. The stiffer the spring the slower the transmission will upshift and the less the belt can slip. The transmission also becomes more sensitive to load and will downshift on hills better. When an engine is modified for more top end power, adding a stiffer spring helps. We used a Malossi red spring for a 50cc Yamaha Zuma. The red spring is the stiffest of three available springs from Malossi. We also used a Malossi torsion controller bushing from a Zuma as well. The torsion controller bushing allows the contra spring to compress freely without bind. This allows the variator to upshift and downshift more freely and smoothly with greater consistency. We got these Malossi Zuma parts from Provo Scooters.
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| We also WPC treated the inside of the variator, the shaft and the ramp plate. This reduces the variator's internal friction and makes it more sensitive to load and allows it to work more smoothly. This nicely complements our contra spring tuning. |
We assembled everything with Dr. Pulley 4.5 gram sliders in the variator, lighter than the 6 gram slider we had been using. The lighter sliders will delay upshifting and help keep the engine in its powerband better. We feel that sliders from 4-5.5 grams will work well for someone with an engine modified to the same extent as ours. When WPC treating the variator, you will need to use lighter weight rollers/sliders as the variator becomes more responsive due to less internal friction and will upshift too aggressively, bogging the engine with heavier weights.
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| We used Dr. Pulley variator sliders to tune our variator. The Dr. Pulley sliders allow the ramp plate to sit 0.020″ lower in the variator at rest. This give a lower gear ratio out of the hole, improving low speed acceleration. We ended up settling on 4.5 gram sliders to tune our variator to our engines' powerband and our weight. |
With these final changes, all we can say is WOW! Our acceleration is now close to what it was with the stock gears with additional top speed and more relaxed cruising at 50 mph. Our scooter also performs well in the hills, pulling a 200 plus lb rider up the steepest hills without dropping below 35 mph ever no matter how steep the hill. Our top speed of 59 plus mph can be reached repeatedly. With a lighter smaller rider, we feel that the Ruckus can probably hit 60 mph. We have turned our Ruckus from an anemic pit bike to something that is a useful commuter that can handle anything below a freeway. After several thousand miles, we are proud to report that our Ruckus is also stone reliable. It still get around 85 miles per gallon, down from around 95 mpg stock but note that is probably going much faster as well!
Are we done? For now yes but we have other Ruckuses being built right now in the Palatial MotoIQ garage. We are going to try further development of theGET engine on another chassis to reach our goal of 60 mph. We have some sick engine swaps in the works as well, both two stroke and big 4 stroke. Stay tuned!
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