Buddy 150 Belt 742x20x28 v 742x20x30?

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dromedary
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Buddy 150 Belt 742x20x28 v 742x20x30?

Post by dromedary »

2008 Buddy Pamplona 150, 14k miles.

Playing around with roller weights, found belt was worn and cracking. Ordered new one from Scooterworks. They sent (as ordered) 742x20x30. Manual says this is right (for 125).

Putting it on I noticed it was a little wider than the old one. Reinstalling variator, everything seemed extra snug. Secured the nut (super tight (I thought)), lit it up, turned up the throttle, whole variator assembly spun itself off. Everything went flying.

I compared the old belt to the new. Old (stock) says 742x20x28. New is 742 x 20 x 30. I assume first number is length around (OD?), second is external width (18 on old, 19.5 on new). What is the third number? Could that be why everything spun out?

Now I've gotta get a new variator, etc because I'll never find all the parts all over the parking lot.

Thoughts?
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charlie55
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Post by charlie55 »

Dimension explanation from the web:

"Belt size is most commonly expressed with 3 sets of numbers, 788 17 28 for example. The first number [788 in our example] tells the belt's length in mm. The second [17] is the belt's width in mm. The third [28] expresses the angle of belt's sides. Sometimes an exact match can be difficult to find, but generally you can find something very close. Very small deviations in size will often work fine. If you can't find exactly what you're looking for try to stay within a few mm on the first number, 0.5mm or less variation for the second, and within 2° for the third."

Your belt is 2° off from the original spec, but that's nothing. If your variator went flying off in pieces, it is almost certainly not the minor difference in belt angle that caused it.
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DeeDee
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Post by DeeDee »

That third number is the angle. It spun out because you probably tightened the variator nut onto the belt and not the boss. Squeeze and rotate the clutch pulleys while you force the belt between them. This gets it out of the way, so you can tighten the variator onto the boss.
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babblefish
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Post by babblefish »

DeeDee wrote:It spun out because you probably tightened the variator nut onto the belt and not the boss. Squeeze and rotate the clutch pulleys while you force the belt between them. This gets it out of the way, so you can tighten the variator onto the boss.
+1 - I've almost had this happen to me but caught the mistake before any aerobatics could occur.
Some people can break a crowbar in a sandbox.
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