I was reluctant to attempt making these changes because of the difficulty NMK had getting the nut off of his secondary, but I decided to give it a try and I am sooo glad I did. Like him, my primary came off with a breaker bar but I couldn't get the nut off of the secondary even with a long pipe on the breaker bar, fearing the worst I loaded it onto the trailer and off I went to my quaint local repair shop and the owner had a small almost cute little impact that had 450lbs of torque and it just fit between the frame and the nut and without using the spanner which I had welded together the impact wrench pulled the nut right off, we did use the spanner when we torqued the nuts back on.
I set the secondary to C1 as Cosmosdan had suggested and installed 25g Dr. Pulley Sliders and I am not sure what did what but it is like a different machine, literally night and day difference. I only had time to run a few miles with it but just heading up my steep driveway about 150 feet long I could instantly feel the improvement in in the low end torque, ran along some flat dirt roads and I didn't have a section long enough to see what top speed was but it hit 45 pretty quick and it had more to go, anytime I punched it I could feel the difference in the low and midrange, the last test was a long hill approaching our house that I will guess is about a 30 degree incline, in the past my machine would not backshift and would just proceed up the hill losing speed and RPM's all the way to the top, not today, today I was actually gaining speed up the hill and had to ease up on the gas as I approached the crest because you can't see over it and I was worried that someone else might be coming the other way.
My belt which has 2500 miles on it is in good condition, the service manual says to change it when the width is 33.5mm or less and mine was at 34.9, I don't know what the width is of a new OEM belt. My primary was packed with hard build up, I guess it was baked hard because of the heat, a garden hose wouldn't even begin to loosen it up I actually had to scrape the dirt out with a screwdriver.
I am at low elevation 500 ft or so and just installed 27"x8.50x14 LT tires I am not sure what the Abuzz tires weigh but these tires are 26.5lbs each and I would guess maybe 5 to 7lbs. heavier than the Abuzz. I stood one side by side with the 26" Abuzz which is worn out and they are about 2.25 inches taller than the Abuzz so I wonder what the actual diameter of a new Abuzz tire is.