Contra Spring Swap-Out

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Wheelman-111
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Contra Spring Swap-Out

Post by Wheelman-111 »

Greetings:

I was reading on an Euro website today. They talked about the tendency of Kevlar-reinforced belts to slip a little more than Stock items, particularly with modded engines running tall gears. The issue hadn't occurred to me before, but makes sense.

The solution? Install a stronger Contra spring to maintain higher tension on the belt. This of course requires adding weight to the variator rollers in order to maintain proper engine RPM. But no doubt that the tigher-jammed belt will grip better.

Downside? The welds on the Driven Face have been known to come apart under the increased tension. Also the tranny will "hunt" a lot more as the dance between centrifugal force at the front and static tenson at the rear occurs much faster when throttle is released and re-applied. Not so good for steady-state cruising, but great for frequent slow-and-go riding in the twisties or on the race track.

Upshot: stock-ish builds should stick to changing variator rollers, as they are quick and easy to swap compared to rear pulley dismantling. But for the Mega-Modding-Minded, a +1000 or 1200 or 1500 center spring suddenly makes more sense. Caution advised on the thick +2000 springs for pulley failure.
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
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