Finally borrowed a 1/2" impact wrench and got these installed yesterday -- found out that NO ONE around here will rent air tools because of the possibility of getting water in them. (My old impact wrench wouldn't remove the secondary.)
Haven't really had much of a chance to test it out -- only one run out of the driveway and down the street. The difference in low-speed RPM and acceleration up to about 20MPH is quite noticeable. Didn't have a chance to wind it out to see if what the top speed is -- assuming that it will still hit the rev limiter with these heavy 26" Hornies on steel wheels.
What was really noticeable was watching it operate during tests before I closed it back up.
(1) At idle and lower RPMs the belt now rides so high in the secondary sheave that the ribs are completely above the edge of the pulley. The edge of the OEM belt (still relatively new with less than 50 hours) goes ALL the way to the top of the pulley. It is perhaps 1/16" of an inch higher than before on the secondary.
(2) The lighter weights really delay how fast the primary sheave starts opening up. It's now somewhere past 1/2 throttle before the sheave starts opening, and it won't open completely until almost 3/4 throttle or so. (It would've been nice to have a tach to see the actual RPMs), At full throttle, the belt is riding at least 1/4" higher on the primary sheave than before -- not quite as high as the secondary sheave at idle -- but all the way to the top of the primary at full throttle.
(3) There appears to be a noticeable "shift point" in how the primary sheave opens, just watching it, but I don't have enough time in the seat yet to see if it is really noticeable on the "seat of the pants dyno." Not sure if this is just an impression based on the delay in it opening, or not.
Hopefully will have more impressions after this coming weekend. We're supposed to ride in a "charity ride" on the backroads and sidestreets on Saturday, then the ATV club has a night ride scheduled for Saturday night.
One tip to relate from this. When I first tried to remove the secondary sheave, the fan was blocking one of the holes that I needed to use to relieve tension on the belt -- it tilted one bolt at just enough angle to where I couldn't get it started in the threads. So I removed the primary sheave with the belt still on. When putting it back together, I positioned the fan on the secondary, then used the two bolts to keep it in the right location while I tightened it down. Don't put them in far enough to contact the inside half of the secondary sheave -- just enough to get them fully-threaded on the outside half. This won't influence the torquing or anything, yet esnures you don't end up with what I began with -- a condition where the fan had shifted slightly during tightening, and blocked one of the bolt holes.
Thanks Steve & Nick!