beware of broken belts

Discussion in 'Battle Scooters' started by JerryH, Oct 4, 2013.

  1. JerryH

    JerryH Banned

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    I just had a belt break on my Vino 125. The belt only had 4,000 miles on it, and was completely destroyed, all chewed up and kinked, with teeth broken off of it. Yamaha says these belts are supposed to last 12,000 miles, and the last 2 did last 10,000 miles, and still looked good. The rollers also only had 4,000 miles on them, and looked like new. In fact, there was NOTHING else wrong. Everything was oem Yamaha. There is nothing to indicate what happened to the belt. And on a Vino 125 this is not a side of the road job, the oil has to be drained and you need a new gasket. I had to wait several hours for someone to come and pick me up 35 miles from home.
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  2. Emanuel_v19

    Emanuel_v19 Adventurer

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    but you had control over the scooter after it broke?
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  3. k-moe

    k-moe Long timer

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    How fast were you going at the time? Did you check the belt for proper alignment when you replaced it for the old one? Belt failures are not entirely uncommon; Yamaha changed the composition of the belt for the 125's about two years ago, but there are probably quite a few of the old belts in stock. Did your new belt have black sides or silver/grey sides?
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  4. JerryH

    JerryH Banned

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    Everything was installed properly, I had done it 3 times on that scooter. I was all Yamaha parts. Nothing was missing or in the wrong place. It did not lock the wheel. It just started to rev like you had pulled in the clutch on a manual shift bike. The engine ran fine, but it wouldn't move. I figured it had to be the belt or the clutch. I had even tightened the variator nut to the proper torque. I was surprised when I took it apart, and saw what was left of the belt. It was running just fine right up to the time it broke. I was riding full throttle at just over 50 mph indicated. I've always ridden it like that.
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  5. gitsum79

    gitsum79 Adventurer

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    Could be just a faulty belt?
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  6. Chillis

    Chillis Land Barge Pilot

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    Good thing it wasn't one of those fancy new e-belts that are electronic!

    Kidding Jerry.

    I would check the variatorand pulley surfaces for anything that could cause excess friction.

    Did the pulley come into contact with the sharp side of a case half causing a cut? This happening if the rear pulley is not removed to change a belt and requiring force to get it past the casr.
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  7. gogogordy

    gogogordy Long timer

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    Make certain there is no blockage on any and all housing air inlets and outlets designed to cool the belt. Heat is definitely the enemy of the CVT belt system.

    Youre lucky the rear wheel didnt lock up.
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  8. blugg1

    blugg1 Been here awhile

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    That's too bad, Jerry. Fortunately you didn't get hurt. As heat is an enemy of belts, you might want to check the vents. Also, it's crazy hot in Chandler about six months a year. That could be a contributing factor. On the other hand you said you had some belts go 10K miles and I assume you were living in Chandler then, too. Which leaves me scratching my bald head.
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  9. JerryH

    JerryH Banned

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    It is a puzzle to me. I have never had the rear pulley/clutch assembly off, but they work fine, and the pulley is completely smooth. The only thing I did notice is there was a build up of rubber around the very outer edges of the front pulley, slightly less than 1/8" wide. Not a whole lot but noticeable. All the openings in the cover were clear, and I cleaned and reoiled the CVT filter on a regular basis. I think it was on it's fifth filter. The filter was fairly clean.

    New belt is here, and I will be putting it back together in the next couple of days. Don't know how far I will trust it now though.
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  10. tortoise2

    tortoise2 Been here awhile

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  11. k-moe

    k-moe Long timer

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    Jerry, the factory service manual specifies that the entire transmission (excepting the final drive gears) be cleaned, inspected, and lubricated every time that the belt is changed. Since you haven't done that, and are on your third belt, you have found the cause of your belt failure.
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  12. JerryH

    JerryH Banned

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    What is it about the rear pulley that could destroy a belt? The pulley faces were completely smooth with no noticeable wear, and the clutch still worked fine. Most of my miles were highway miles. What should be replaced on the rear?
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  13. Midnullarbor

    Midnullarbor Been here awhile

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    .
    Coincidence of a "bad" belt is (we hope) the likely thing.

    Though not in this case, a contribution from worn pulleys is usually on the cards.
    I look forward to the day that manufacturers get around to using steel-faced pulleys.



    Blugg raises the important point of heat-vulnerability of belts; and it needn't be just poor ventilation or bad pulley bearings.
    Sheer environmental heat [summers, or tropics] is also bad news for belts.
    It is a major weakness in standard scooter design.

    ~ Not so easy a matter to fix, I think.
    Quite a re-design would be needed to make for quick-n-easy road-side replacements of belts [and with minimal tools].
    Meanwhile we'll just have to wait for technological advances in belts.

    .
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  14. blugg1

    blugg1 Been here awhile

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    The problem could be solved completely if scooter manufacturers would return to transmissions. No pulleys, no belts, no sliders. A clutch? Sure, but it's cable operated and you only operate it when you shift. I don't know enough about scooter history so I'll ask this innocent question: When did twist 'n go come into fashion? And why did manual transmissions disappear?
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  15. JerryH

    JerryH Banned

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    Seems like they became popular in the '80s in the U.S. with Japanese scooters. Many people don't want to shift. I have a Stella with a manual transmission, and it if fun to ride for short distances, but it gets old in a hurry riding through stoplight after stoplight in town.

    Many cars use CVTs, and they all seem to have short lived transmissions. I looked at the Nissan Versa and Sentra, which have CVTs, and keep hearing the transmissions fail after 30,000-40,000 miles. I was also looking at the Chevy Spark, but they changed to a CVT on it for 2014. It seems the concept has been around for a long time, but it never became popular due to reliability issues. Subaru used to sell a car called the Justy here, with a CVT, but it was considered unreliable for long distance travel (like I use my Vino for) and was designed more for city use. It appears a CVT is not the best thing for long distance riding/driving. I keep hearing about maxi scooters with a lot of highway miles on them, maybe they have a more robust setup than the smaller scooters. I also don't know how many belts they have been through.
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  16. k-moe

    k-moe Long timer

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    IIRC CVT transmissons have been in scooters since the mid to late 1950's

    The advanages include a lower learning curve for the rider, and better fuel economy (always being in the right gear).

    Jerry, If the torque driver isn't serviced regularly the rear pully won't open smoothly, nor will it open fully at speed. As the grease ages, and dries out, it also begins to hinder movement. In addition the pins in the torque drive begin to wear into the slots, and the bore of the movable sheave begins to get out of round. The result is the variator fighting against the torque driver (more than it usually does) trying to adjust the rear pully. The belt heats up (beyond the normal amount), stretches (the total distance the belt has to turn around is lengthened when one pully isn't moving in synch with the other), and shreds. The whole proces is exacerbated by the tendency for U.S. riders to spend longer periods of time at higher speeds.
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  17. JerryH

    JerryH Banned

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    Well I guess I will pull the rear assembly apart and check it out, and replace any worn parts before putting it all back together. I have the service manual, but I didn't think there was anything back there besides the face of the sheaves and the clutch that could go bad.
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  18. blugg1

    blugg1 Been here awhile

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    DaBears: Thanks. I learned from your post. Much appreciated.
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  19. Shirker

    Shirker Been here awhile

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    In '64 I was riding a 61 Lambretta Li150 - newfound freedom for me, cheap transportation and fun.
    Here's a youtube of a similar scooter, watch his left hand, what could be easier? Before you ask, the rear brake was a footbrake.
    http://www.youtube.com/watch?v=JtxMy1vLrSg
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  20. cdwise

    cdwise Long timer

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    Or a Stella, though I was talking to the local Genuine dealer this weekend and he was saying that he has folks lining up for the new automatic Stellas that are coming in. He was saying that the majority of people who come into the shop intending to buy a Stella end up not doing so because they don't want to shift. In town where scooters really shine twist and go has so many advantages with all the traffic lights, stop signs with stop/go traffic.

    Personally, I like shifting cars but not living in places like San Francisco where hills combined with traffic and lots of lights/stop signs takes all the fun out of it. I didn't have m/c in San Francisco but I wouldn't want be riding a manual there either. Scooters on the other had are easy peasy in town. Heck, I've got a paddle shift option on my car but the only time I'd use it is the mountains not in Houston or Denver.
    #20