Some more substantive content for interested minds. I have a feeling this one's going to attract a lot of trolls, so please take note of the disclaimers posted below the overview.
Overview:
Using a wider (than stock) belt on the Urban is a popular way to increase the bikes maximum obtainable speed.* The general theory being that the increased width causes the belt to sit higher in the variator, which in turn gives a better drive/driven ratio. But the increased width also means that the belt may not be able to sink as low in the rear pulley (which would limit top speed). The steps below show one approach to mitigating that factor by increasing the amount by which the rear pulley face-plates can separate.
DISCLAIMER & NOTES:
- This has been mentioned on the forum before, and is a widely know trick in the scooter-world; I did not invent this technique in any way.
- This is potentially dangerous and/or unnecessary. If your belt sinks too low in the rear pulley, it could get stuck (belt too short). If the belt rides to high in the variator, it may come off entirely (belt too long). Know what belt-length you're working with before attempting this. NOT RECOMMENDED FOR STOCK BELTS.
- If you're engine is already maxing its power output (with a current setup), this may not do anything at all (except mess with RPMs - in a bad way).
Step One:
Remove rear pulley. Disassemble (including collar, but not internal bearings). I took this opportunity to clean up some heavy pitting and rust; a few minutes in the lathe had things looking good.
