One of the things that had distinguished our 2007 Buddy from the 2009 was ride quality and handling characteristics. The 2007 had spent a long time living outside in the elements, while the 2009 has been garage kept since day 0. The 2007 has always felt a little more rough. Part of this may be attributable to more mileage and being broken in and ridden hard, but part was obviously wear and tear in the drive line. The 2007 had been particularly known for surging transmission behavior. Sometimes it would accelerate hard, at other points it would hunt a bit at fixed throttle positions, or hesitate to down shift while slowing down (nearly stalling the engine at one point). This behavior was relatively subdued and was never severe enough to warrant diagnosis.
At the outset, I had inspected and found the drive belt to be worn to the limit (19mm if I remember correctly), and thus ordered another, which I then set out to install.
The Buddy's drive line cover is held in by a large number of small bolts, and while there is a gasket, oxidation and the post for the kick starter keep it snugly attached. I gently tap it on the side with a mallet to wiggle it free. The cover also contains the half moon gear and fast drive for the kick starter. You can also see an air vent at the back of the cover (left of this photo, front of bike is at the right). The case is actively vented by a fan impeller cast onto the variator drive face. The kick start teeth (right of the photo) engage a splined washer on the front of the variator drive face.
View of the inside of the drive line. The variator drive face is at left (also front of scooter) the clutch bell is at right. The variator and the clutch are on splined shafts (output shaft of engine and driveshaft of rear axle, respectively), and the speed control components (the variator moving face, the belt, the rear pulley with contra spring, and clutch) freewheel behind the splines. The manual says the the nuts on holding the clutch and variator on are at about 35 ft-lbs. They came right off using an impact wrench. Note that the kick starter engagement washer is splined as well, and it will need to be properly aligned in order to put the variator back on!
Variator drive face removed. The limits of the belt engagement are visible.
The variator moving face.
Buddy 125 clutch bell.
While dusty, the clutch surface was neither grooved nor glazed. I left it alone.
Drive belt nearly free. You can see the centrifugal clutch components at right.
Detail of belt and variator. The belt is wide enough that the variator plates never touch.
Clutch made in 2007. Clutch pads look acceptable.
Clutch pads up close.
Backside of clutch assembly. There's a roller bearings in there!
Detail of the clutch roller bearings. They ride in a carrier. When I first saw them, I worried the carrier was damaged as the central groove was so full of grease and grit that it looked like it had maybe been warn through, but some cleaning revealed that it was intentional. Perhaps a lub reservoir? I added a dab of grease to it.
Backside of the variator. The rollers press against the plate to push the variator halves apart at high RPM. The white platic bits are gliders. Dusty! I wonder what the blue paint marks are there for?
At this point, I set the variator aside to look at the belt I had just removed (remember the belt?). New belt looked pretty similar.
Old belt: Bando Nylon 743x20x28
New belt: Gates Powerlink Kevlar 743x20x30 PL30707. I read these don't last as long, but I didn't know that when I bought it.
Back to the variator. I pulled the cover and looked at the rollers. Wow! Dusty!
All of the rollers (at 6000 miles) were just barely out-of-round.
A worn spot
Another worn spot.
Rollers in their races.
I ordered some replacement Dr. Pulley Sliders. The Buddy 125 comes with 18x14mm 11.5 gram rollers stock. I decided to try heavier sliders (12 g) to see if I could get some more top speed.
Sliders installed in their races.
Putting the drive line back together was a lot easier when I found I could push the clutch pulley open with my hands and wedge the drive belt in to keep it open, creating a little slack on the variator pulley to make it easy to align the kick starter splines and the variator drive face with the engine output shaft spines. I used a strap wrench and a torque wrench to get the nuts back to 35 foot-lbs.
The sliders immediately improved the quality of the power delivery, and the engine and drive line. The heavier sliders definitely reduced acceleration off the line, and though the scooter has better acceleration in the 35-50 mph range, it doesn't seem to want to go faster overall and hill climbing is also a bit worse. For this bike at least, 12 g sliders are too heavy and suboptimal and I'm likely to go with something lighter in the end, though for a rider that prefers more demure handling, the 12g might be an improvement.... the front wheel won't ever leave the ground with them installed.
Thanks for the write-up! I just acquired a 2007 Buddy 150 - and discovered your site! Chuck
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