CLUTCHING at SPRINGS
Posted: Wed Feb 25, 2009 12:36 pm
Greetings:
With the recent most generous but failed attempt by ScooterWerx to provide me with Monster clutch springs, my limited brain capacity has turned to the question of clutch engagement speed.
One way to affect the clutch behavior is to change the stiffness of those three springs inside the bell. If I want the clutch to engage at a higher speed, simply install stronger springs. They fight/balance the centrifugal forces generated by the three clutch shoes and determine the RPM at which the clutch starts to... uhh, you know - Clutch. Stronger springs needs more revs before the shoes start their outward swing. But is there another way?
An Old snowmobile trick was to drill material out from the kidney-shaped clutch weights, making them lighter. Like small-displacement scooters, modified sled engines were pretty gutless at low revs, so this put the engine into its powerband before being asked to supply propulsion. It's a bit more of a PITA on a scooter, because it requires disassembly of that pesky 39mm nut each time. On the other hand, the cast aluminum drills a whole lot easier than the old steel snowmobiles' steel counterweights.
Now you wouldn't want to remove too much material, lest it need to wind out to stratospheric levels before engagement. But I think it'll work. I have nifty HF scale to balance things pretty closely. Has anyone done it? If so: How many grams (or what percentage) should I shave to start?
With the recent most generous but failed attempt by ScooterWerx to provide me with Monster clutch springs, my limited brain capacity has turned to the question of clutch engagement speed.
One way to affect the clutch behavior is to change the stiffness of those three springs inside the bell. If I want the clutch to engage at a higher speed, simply install stronger springs. They fight/balance the centrifugal forces generated by the three clutch shoes and determine the RPM at which the clutch starts to... uhh, you know - Clutch. Stronger springs needs more revs before the shoes start their outward swing. But is there another way?
An Old snowmobile trick was to drill material out from the kidney-shaped clutch weights, making them lighter. Like small-displacement scooters, modified sled engines were pretty gutless at low revs, so this put the engine into its powerband before being asked to supply propulsion. It's a bit more of a PITA on a scooter, because it requires disassembly of that pesky 39mm nut each time. On the other hand, the cast aluminum drills a whole lot easier than the old steel snowmobiles' steel counterweights.
Now you wouldn't want to remove too much material, lest it need to wind out to stratospheric levels before engagement. But I think it'll work. I have nifty HF scale to balance things pretty closely. Has anyone done it? If so: How many grams (or what percentage) should I shave to start?