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Post by steve1297 on Jul 6, 2021 20:05:13 GMT -5
If you have a 139qmb scoot with 12" tires, you probably use the 729 18 30 belt. I do. Put a 52mm BBK on.
I accidentally ordered a Bando premium belt that was size 723 17 28. The performance increase was marked. Extreme. Torque for acceleration and hills improved greatly. Top speed went from about 55 to 48, but maintaining speed is so much easier. Keeps 40 mph up pretty steep hills, where it would slow to 30 before. Also, 8g variator weights work for me. About 6500 RPM seems to be the power band with my motor, anyways.
The 723 17 28 belts are readily available. Made by Bando, and won't hurt your CVT. The increase in torque is remarkable.
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Post by snaker on Jul 11, 2021 10:44:28 GMT -5
Sounds like your using the CVT pulley ratios to adjust your gearing.
If its working for you, then there ya go.
But a "gearing" change within the CVT is most likely also reducing the gear range of the CVT.
Something in the CVT is the mechanical limit to the variable pulleys on both ends(low speed and high speed) and there's a good chance the new belt may be changing that, possibly bottoming out in the driven pulley earlier.
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Post by captincvmn on Jul 11, 2021 11:18:11 GMT -5
It makes sense that with a lower top speed your mechanical ratio for high gear is lower. This would make climbing hills easier. Some people go for high top speed, some go for quick launch, it’s personal preference. I like RPMs to stay in power band and have the CVT downshift (doesn’t really shift, just changes ratios slowly) as I go up a hill so my speed doesn’t bog down to nothing.
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Post by steve1297 on Jul 14, 2021 14:34:15 GMT -5
Sounds like your using the CVT pulley ratios to adjust your gearing. If its working for you, then there ya go. But a "gearing" change within the CVT is most likely also reducing the gear range of the CVT. Something in the CVT is the mechanical limit to the variable pulleys on both ends(low speed and high speed) and there's a good chance the new belt may be changing that, possibly bottoming out in the driven pulley earlier. It definitely changes something. I think it may be the .4mm reduction in width as much as being slightly shorter. It definitely reduces top speed a little. But I don't need to go 60. With a 52mm BBK, and a 24mm OKO flat side carb, and this new belt, I can cruise up and down hills at 45mph, and it's very quick. Very quick.I got it up to 53mph yesterday, just to see. That's about all she'll do. But if you don't have a BBK, and Don want to lose as much speed on hills, this would be a great option. |
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