this purpose a first terminal end 92 of a wire forming the spring 84 is bent radially inwardly alongside one of the projections 74 of the fixed pulley half 60 while a second terminal end 94 of the wire is bent radially outwardly and extends through an aperture provided in an axially extending flange or rim portion 96 of the indexing plate 88 also the plate 88 is normally prevented from rotating about the abutment member 64 by means of a plurality of splines 98 only one shown equiangularly arranged about the abutment member 64 and received in complementary notches 100 located in the plate 88 as can best be seen in fig4 the splines 98 extend axially toward the pulley half 60 only a short distance from the shoulder 90 this permits the torsional preload of the spring 84 to be adjusted by fitting a special tool to notches 102 provided in an outer rim of the plate 88 and moving the plate axially beyond the splines 98 and rotating the plate 88 clockwise fig3 to increase the load or counterclockwise to decrease the load once the plate 88 is in that angular position which corresponds to the desired preload it is permitted to move back against the shoulder 90 where it once again is restrained from rotation by the spline 98 appropriate indicia is provided as at 104 on the abutment member 64 and indexing plate 88 so as to aid in making the desired adjustment the operation of the snowmobile transmission and particularly of the secondary pulley 32 is as follows it being noted that the operation of the primary pulley 30 may be assumed to be the same as that of.