Author Topic: Belt keeps shredding  (Read 1744 times)

szamar23

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Belt keeps shredding
« on: October 26, 2022, 06:08:00 PM »
Hi!
I bought a Kymco Agility 50 7 months ago, originial 1700kms, like brand new, with the drive boss resctrictor still in. I replaced the drive boss and put on an off brand drive belt and after 500kms it shredded suddenly. The scooter just started bogging down and then bang >:( . After that I replaced it with a quite expensive original Dayco belt. It drove 3000kms  8) then bang exact same scenario. Recently I put a Gates belt in and It was gone also gone after about 1000-2000kms. I took it to a shop to check out my whole cvt drive and they couldn't find anything wrong. Once I actually checked the belt 2 days before it was shredded and it was in perfect condition. I have absolutely no idea what could be wrong. It is completely stock, only the drive boss is derestricted. I attached a picture of the shredded belt. Thanks for all the help!
« Last Edit: October 26, 2022, 06:10:04 PM by szamar23 »

CROSSBOLT

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Re: Belt keeps shredding
« Reply #1 on: October 26, 2022, 10:28:26 PM »
I do not recall the brand of belt in my 2006 Agility 50 but I seriously doubt Dayco as oem on any Kymco. The picture of the shredded belt suggests excessive heat. Heat is normal for all "rubber band" CVT's but excessive heat is from slippage. Belt slip can be from wrong "V" angle of belt (wrong belt), too long or too short a belt maybe, improper assembly of front pulley or incorrect spring in rear pulley.

My first recommendation is reliably determine what the original belt was and get an original replacement. Second, make ABSOLUTELY SURE on the front pulley the washer between the sleeve and the engine, next to the engine has the inner diameter chamfer NEXT to the engine side. Third, check the color of the big spring on the rear pulley (not clutch shoe springs--they are little). I think mine was white but verify with a reputable dealer or authentic parts diagram. Finally, back up on the front pulley, the most common mistake is not getting the stationary (outer) plate/pulley half seated COMPLETELY before tightening the nut. This usually destroys the front pulley. It may be able to destroy the belt as well.
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

Iahawk

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Re: Belt keeps shredding
« Reply #2 on: November 07, 2022, 05:23:13 PM »
Now THAT'S an answer..wow! way to go, Karl! Great stuff!
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stuo

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Re: Belt keeps shredding
« Reply #3 on: November 07, 2022, 06:34:56 PM »
I would install a cheap belt, leave the CVT cover off, put it on the center stand (or rig up a center stand) and watch the action of the CVT/belt as I worked the throttle. Then I would ride it a while, stop and feel all the parts for excessive heat and wear. Also check to make sure the CVT air vent is not blocked.

I have a buddy who rides a scooter without a CVT cover! He said he avoids puddles and dirt roads and hasn't had a problem. Although I wouldn't do that it seems leaving the cover off might help you find the problem in this case.
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CROSSBOLT

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Re: Belt keeps shredding
« Reply #4 on: November 07, 2022, 10:26:20 PM »
I would install a cheap belt, leave the CVT cover off, put it on the center stand (or rig up a center stand) and watch the action of the CVT/belt as I worked the throttle. Then I would ride it a while, stop and feel all the parts for excessive heat and wear. Also check to make sure the CVT air vent is not blocked.

I have a buddy who rides a scooter without a CVT cover! He said he avoids puddles and dirt roads and hasn't had a problem. Although I wouldn't do that it seems leaving the cover off might help you find the problem in this case.

What stuo said!

Thanks, Hawk!
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

szamar23

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Re: Belt keeps shredding
« Reply #5 on: November 08, 2022, 07:05:26 PM »
Thank you for the tips guys!
I did all recommendations and found abosolutely nothing wrong. Even got 400km-s on the new quality belt and checked again but still absolutely no pre-signs of any issues. The belt was always the exactly perfect size. Since it is my main source of income (i work as a food courier), I came to the conclusion that I'm going to sell it. Thank you so much for the help. I think I'll stick with honda from previous experiences ;D

CROSSBOLT

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Re: Belt keeps shredding
« Reply #6 on: November 08, 2022, 11:57:09 PM »
Thank you for the tips guys!
I did all recommendations and found abosolutely nothing wrong. Even got 400km-s on the new quality belt and checked again but still absolutely no pre-signs of any issues. The belt was always the exactly perfect size. Since it is my main source of income (i work as a food courier), I came to the conclusion that I'm going to sell it. Thank you so much for the help. I think I'll stick with honda from previous experiences ;D
Honda is a sure bet. Nearly as tough to kill as a Toyota. Too bad Toyota doesn't make motorcycles or scooters....
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

punktnet

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Re: Belt keeps shredding
« Reply #7 on: January 30, 2023, 09:05:42 AM »
When install the CVT cover, make sure the hose is not bent. I've had the same issue and figured out that position of the vent hose was NOK and the CVT was overheating

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