Pulley Adjustment



For more competitive performance, or better fuel economy, the user may increase or reduce engine acceleration speed. The Weights in the Blocks determine engine speed.

The lighter the Blocks, the higher the engine RPM.

In general,

In the case of the Powerbloc ALT and 50, adding a # X-81-3 Weight (3.4 grams) to each of the 3 blocks reduces engine speed by 100 RPM (Refer to the Chart).

In the case of the Trailbloc, Weights are available in 2-gram increments. Adding 2 grams to each of the 6 blocks reduces engine speed by 100 to 200 RPM.

The opposite is also true if one wants to increase engine speed, and this effect is cumulative, if one adds or removes Weights.

 To ensure proper Pulley equilibrium, the blocks must contain precisely the same number of Weights.


Though Block weight has a direct effect upon the engine RPM at which the vehicle starts moving, it is mainly the choice of Spring that determines Pulley speed engagement. There exists a wide selection of Springs for the CVTech Pulley range.

CVTech Pulleys are pre-calibrated in plant, thereby offering an engagement speed that satisfies most users. However, engagement speed may be modified by changing the Spring. A lighter Spring will reduce the engagement speed, thereby allowing for smoother starts and improved vehicle control at very low speed. Inversely, a heavier Spring will produce starts which are more abrupt and competitive.