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Lets talk about belt cooling

AwDang

AwDang

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I’ve read varying reports on belt life around the web. Most point to heat being a major factor in their demise. Every scoot i’ve had has some sort of air intake for the belt case. But I’ve yet to see an exhaust opening to let heat and air out.

Has anyone experimented with improving belt cooling?
 
AwDang said:
I’ve read varying reports on belt life around the web. Most point to heat being a major factor in their demise. Every scoot i’ve had has some sort of air intake for the belt case. But I’ve yet to see an exhaust opening to let heat and air out.

Has anyone experimented with improving belt cooling?
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Every Scooter I have owned has had an air inlet as well as an exhaust for the CVT. Most of them also had an air filter for the inlet. I have had two belts fail on my Like 150i. I think part of the reason was that I failed to clean the air filter. As for all of my other scooters, I have never had a belt fail and I have put up 18,000 miles on a belt and it still looked good when I replaced it.
 
AwDang said:
I havent see exhaust holes
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they are on the bottom rear of the CVT. There is a cooling fan on the variator that draws air in from the air intake near the front of the variator case and it exhausts near the rear of the case.
 
Nothing personal, and I get you have almost 50k on stock scoots. I’m looking for people who have tried NON-stock ideas. I’ve toasted 2 belts, 1 on the Like and 1 on the Vespa due to sustained full throttle riding.
The GY6 Ruckus crowd seems to like open belts. That might just be for cool points tho.
 
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AwDang said:
Nothing personal, and I get you have almost 50k on stock scoots. I’m looking for people who have tried NON-stock ideas. I’ve toasted 2 belts, 1 on the Like and 1 on the Vespa due to sustained full throttle riding.
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I have well over 100K miles on stock scooters and all of them have seen sustained running near top speed except my Majesty which tops out over 90MPH. The only one that has given me any issue is the Like which snapped the original belt at 10K and the next one at 7.3K.

Here is why I think the Like is hard on belts: One, there could be a cooling issue. Part of that may be the design and part is due to a dirty CVT air filter. Another issue is that the rollers on the like get really bad flat spots. This makes the variator operate in a jerky manner which puts extra stress on the belt. It may also cause vibrations in the variator further stressing the belt. In the future I will replace the rollers at 5-6K instead of with the belt.

As for Vespa's, a lot of them have been used in extended high speed riding. A friend bought a used Vespa 250GTV. I know the PO rode it really hard. We replaced the belt at a little over 12K and the belt and rollers looked fine. The Vespa's have a CVT air filter that is just a small piece of foam. Make sure it is clean.

I would go to the Modern Vespa Forum and ask about this issue. I know some people go with aftermarket Variators. Possibly the aftermarket variators have a larger cooling fan?
 
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I've seen some major cutouts on the CVT cover on tuned 50cc scooters.
The quality of the belts you buy also has major impact on life expectancy.
90GTvert at 49ccscoot forums has written a bit about the cooling issues and shows some modifications. https://49ccscoot.proboards.com/thread/360/cvt-cooling

If you want to play around a bit. Belts that are few millimeters longer or shorter will change your gearing.
 
Amos Malone said:
I've seen some major cutouts on the CVT cover on tuned 50cc scooters.
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The problem with doing that is the potential for grit or water to get into the CVT. Not a big issue for scooters run for short distances in nice weather but it would be for long distance riding.
 
Amos Malone said:
I've seen some major cutouts on the CVT cover on tuned 50cc scooters.
The quality of the belts you buy also has major impact on life expectancy.
90GTvert at 49ccscoot forums has written a bit about the cooling issues and shows some modifications. https://49ccscoot.proboards.com/thread/360/cvt-cooling

If you want to play around a bit. Belts that are few millimeters longer or shorter will change your gearing.
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Awesome!
No need to change ratios at all. I can get speeding tickets in every state but Texas.
 
Nearly forgot. No, I did forget.
Pulleys out of alignment can cause premature failure of belts.
 
Amos Malone said:
Nearly forgot. No, I did forget.
Pulleys out of alignment can cause premature failure of belts.
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Not the issue.
When I do an ironbutt it’s 3hrs at or near full throttle, then a <15min stop to another 3hr stint. It’s pretty much as close as you can get to constant duty.
 
ZoomerP said:
How much weight are you hauling?
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The wind resistance is a bigger factor than the weigh. But i’m not seeing how that relates to mods for additional cooling. As Klav eloquently stated a “normal” rider doesn’t have an issue with overheating belts.
 
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ZoomerP said:
I can see that, but a lot of weight is also going to stress the drivetrain, leading to more heat. A big person may also add to the wind resistance.

I hope you get it figured out. Fragging a belt in the middle of a long ride can't be fun.
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The last one was 45mi from home and only left a pile of dust with cords all wrapped up in the clutch.
 
Here's my experience with scooters and belts.

Kymco Super 8 150. 33,400 miles with no belt or roller issues. I ran that scooter very hard.
Aprilia Sport City 250. 25,000 miles. Replaced the belt and rollers every 12,500 miles. Belts and rollers looked fine. I ran that scooter pretty hard and often ran at high speed on the highway.
Yamaha Majesty. I replaced the belt and rollers at 18,000 miles and they looked fine. At 29,400 miles now. I'll probably replace the belt and rollers around 33K.
Kymco Like 150i. I ride it a lot at 50-60 MPH. Belts broke at 10K and then 7.3K later. Rollers looked really bad.
Yamaha Smax. Didn't own it long enough to replace the belt or rollers.

So why have I had issues with the Like and not the others? I don't know but it's both the belt and rollers that have been wearing out to fast. I inspected the pulleys looking for rough spots but didn't see anything. Maybe the belts and rollers are just lower quality? Maybe the airflow isn't as good and it's the heat. Maybe the worn out rollers put stress on the belt? I don't run it any harder than I did the Super 8 but it does have a bit more power. Maybe I should try sliders.

I think that competitors in the Scooter Cannonball often carry spare belts and rollers. I have heard other people have issues with rollers flat spotting but I haven't had that issue except for the Like.
 
klaviator said:
The problem with doing that is the potential for grit or water to get into the CVT. Not a big issue for scooters run for short distances in nice weather but it would be for long distance riding.
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As long as you are on a good surface, in nice weather, some minimal extra cooling holes should be okay. Strategically placed would holes allow grit and water to get out too. It will also run cooler, but if you need it to run cooler is debatable.

Full CVT rebuild with quality parts while checking for (or adjusting) alignments should make your scooter drivetrain reliable. If people worry about heat. Temperature meters can be cheap and easily added.
 
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