After looking into the theoretical side of rollers and springs. I decided to take some of the guesswork out of my choices. This resulted in a tool that calculates and graphs both of them in relation to each other.
The tool is specially made for Buggy News. Any spring and roller weight(s) can be calculated. For any buggy that has a CVT...
As long as you have the exact (!!!) measurements on the spring. So post your spring measurements and along with any comments and wishes you have for this tool.
Please note that this tool doesn't tell you which spring or roller to buy. But it will give you an idea what the relation is between the rollers and spring along your powerband.
_________________ Buggy: Carter GTR 250 all black. Mods: Mikuni TM33-8012 flatslide + custom manifold. MX-filter, Hit Clutch, Malossi Yellow spring, Racing variator, 16.5 gr rollers, Iridium sparkplug, Custom front and rear shocks, Heavy duty front struts. In-ex snorkel.
Thanks... It's actually that difficult to use. The only thing you have to measure is diameter of your variator and the spring diameter and wire thickness (with a slide caliper). The rest is all calculated by the tool.
In the graph you'll see the combined weight of the rollers along the rpm. And the force of the spring pushing on the back pully. The crosspoint of these lines is the point where the CVT start shifting up. The closer this point is to max. torque rpm the more torque you get at low gear.
Of course lots of other data can be derived from it... asume you have 2 springs and want to know which is the stiffer one... just measure the OD and wire thickness and put in the numbers in the spring calculator section.
Jackster
Attachments:
SpringRollerCalc_calc1.jpg [ 220.37 KiB | Viewed 153 times ]
SpringRollerCalc_calc2.jpg [ 160.84 KiB | Viewed 109 times ]
SpringRollerCalc_graph.jpg [ 88.97 KiB | Viewed 87 times ]
_________________ Buggy: Carter GTR 250 all black. Mods: Mikuni TM33-8012 flatslide + custom manifold. MX-filter, Hit Clutch, Malossi Yellow spring, Racing variator, 16.5 gr rollers, Iridium sparkplug, Custom front and rear shocks, Heavy duty front struts. In-ex snorkel.
Carter GTR 250 MRP Exhaust, Dr Pulley Hit Clutch, Red Main Spring, Dr Pulley 18g Sliders, UNI 6" w/K&N PreCharger, 17t Sprocket, ITP MUDLITES, Dell'orto 30mm Carb, custom manifold
Thats the way to do it. You make it sound simple but you got some brains in this. Great job man. It might do all the work for you but you still came up with this whole thing yea?
Wow! Very nice! Does anyone know the specs on the stock cfmoto250 variator and the blue polini torque spring? I don't have a sliding caliper to measure them... It's on the long list of tools to purchase...
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