PMVK0001 variator kit with 14.5gr rollers, 1.5mm outer shim and red TQ spring ( +10% over stock) (Black TQ spring is stock) has been optimized on our dyno for the following set up.
- PM59 Exhaust
- Dell'Orto PHBH25
- PM Pro-Street 172cc cylinder kit
- BGM 52mm Race Crankshaft
- Kevlar drive belt type:
- option 1 Polini P248018 use 14.5gr
- option 2 Malossi M618739 belt use 13.5gr
- Malossi delta clutch
- PM clutch bell
Calibrate the variator for alternative set-ups. The basic task of the variator and roller combination is to maintain peak RPM power during acceleration, right up to the point where the pulleys are fully extended and finalised. At this point the motor will go into over-rev (above peak HP rpm) to further increase terminal speed. The idea of the roller weights is to keep the variator on the sweet spot, E.g. the above set-up produces peak power at 8200 rpm, then a correctly set up variator should show 8200 rpm target all the way up the speed range to a point where the variator is fully extended.
If the motor runs below 8200 rpm then lighter rollers will be needed, above 8200 rpm -heavier rollers will be needed. The drop or increase in weight to achieve this depends on how far off the target rpm is. As a general rule of thumb 0.5 gr usually equals a change of around 100-150 RPM when working within 500 RPM of target peak power, anything outside 500 RPM of peak power and a 0.5 gr change can make a considerable difference.
Roller weights can be mixed as long as they are placed alternately in the variator ramps in order to maintain the balance. Use the lightest black TQ spring to start with, usually suitable for motors under 24 HP at the rear wheel, red +10% for machines over 24HP.
Because there are so many variables the above information is only intended as a guide, the best way to optimise rollers /belt and TQ spring combination is to dyno test with an experienced operator.