Finnally installed doctor pulley weight (18 grams) form scootertrap. My results are not finall nor normal considering the following factors:
1) Belt has considerable wear. (6,000 rpm@ 70 mph when belt was installed go up to 6,300rpm previous to weights install)
2) Cannot remove the rear Polini belt tensioner spring 'cause cannot find the wrench that I used to remove and install the nut. :oops:
Results:
6,300 RPM@ 70 mph(indicated) go down to 5,700RPM @ 70 MPH. (cruising speed)
Full throttle launch approx 6,300rpm up to 42mph approx. From there, RPM goes up to 7,000 rpm to near 70 mph, then it dropp, like an automatic transmission "shift", to 6,500 RPM. While MPH goes up, RPM continues until like 7,000 RPM @85MPH. I will not test over 85 'cause rear wheel is severely weared. I will get a new tire this weekend.
Also this "shift" caracteristic of this rollers can be used cruising from approx 50mph+ to lower engine RPM's.
For my results unil now, I think this dr. pulley weights are perfect for people who would like to eliminate RPM drop when launching the bike, without increased crusing RPM's, better fuel economy and lower high speed cruising RPMS.
Remember.... RPM results are higher than normal 'cause the polini rear belt tensioner spring.
Also, Dr.Pulley weight has two options, 18 grams(which I installed) and 15 grams. I think does with 15 grams would be a real choice for serious performance guys without sacrificing top speed.