New belt shredded in less than 10 miles..why? By looker (Read 7,299 times)

[looker]

Hi guys,
took my scoot out today after fitting a new Gates Powerlink belt because I had a problem with the scoot pulling away slowly the other day.
Thought it was the belt as it felt a bit loose and it's width had reduced. Could'nt see any other obvious problems so changed it and thought that would be that.
After the new belt was fitted the same slow pull away problem came back, decided to cut the ride short and head home. Got a few miles from home and I could feel a shaking or vibration. About 1/2 a mile later the engine revs shot up and I lost drive.

This is what I was greeted with when I pulled the belt cover off,





and what's left of the belt,



A short while ago I spotted this at the end of the case,



did'nt look or feel like oil, more like grease that had broken down and leaked out of somewhere. Not being able to trace where that hole came from, I cleaned it up and kept an eye on that hole to see if anymore came out. None did.

Pulled the clutch assy off today and the grease that should be lubing the bearings is now black and more like treacle, and the needle roller bearing moves but it's a bit tight.
Could this be what I found on the case? (still can't trace where that hole goes) the last of the bearing grease?
Could that bearing have been running so hot now that the heat transfered to the clutch pulley and melted the belt?

I'm a bit stuffed now. Can these bearings be bought seperately does anyone know, and from where?

If not, it's a whole new clutch, strip it down, clean it out and re-grease the bearings with some proper LM grease.

If anyone else has had this problem and found a fix, please let me know.
At the very least, I hope this brings to other peoples attention to keep an eye on those bearings and the condition of the grease so it does'nt happen to them.

Many thanks,
Mike

[Alleyoop]

Looker,
From what I am seeing, looks like the Belt was riding on the Contra Spring in your Clutch for it to tear up all the teeth off the belt and the sides like that. I would question the Length of the belt, in the pictures the Belt is Down in the Variator and Down in the Clutch Pulley and it already appears to be TIGHT so to me it does look like you have the wrong size belt in there. A to small of a belt could cause what happened to your belt it would pull the Belt TO FAR down in the Pulley Clutch and be hitting the Contral Spring tearing it up.

The other thing I noticed is that You Already Have a 115mm Variator That is the Same Size as your Fan Plate, so I would question why you would need to spend money for a Perferomance Variator which would be 115mm .
Just a thought
Alleyoop

[Bashan]

Hey Mike, just a question out of left field.....does your rear wheel turn easily and the clutch housing with it? I can't figure out where that grease is seeping from and I'm wondering about your transmission (the gears). Rich

[looker]

Hi guys,
Alleyoop,
belt was an 842.20.30, scoot came with the 835. Variator is actually 107mm, so's the fan plate. I'm leaning towards the problem being caused by the bearing running too hot and the clutch over heating. What should be grease is now just a sticky and hard black mess. Scoot ran fine before this happened.
Sequence of failure is as follows, about 5 miles into ride it started the same pull away slowly problem, 1 mile latter the brakeing effect off the throttle started, pulled over and could smell that warm rubber smell (like a new tire smell) touched the belt cover and the rear was a lot hotter than the front. After a short while continued towards home, mile a so later the shaking/juddering started, before I got the chance to stop in a safe place the revs shot up and I lost all drive. Pushed the scoot the remaining 2 miles home.

The belt looks so low in the pulleys because it's actually turned through 90 degrees at those points, which again leads me to think of a heat problem.

Rich,
wheel and clutch turns fine, both before and after what happened to the belt. I can't see how that stuff would have come from the bearings in the clutch, the oil seal on the shaft looks fine and there's no evidence of grease or oil of any kind beihnd the clutch once it's been removed. Changed the gear oil a couple weeks ago and still looked new in color and feel. Whatever that is on the trans was also of a thick consistancy and kinda 'rubbery' between finger and thumb.
The rear wheel was also off about a month or so ago (and after that black stuff appearred) to be taken to the shop to have a new tire fitted, and I could'nt find anything that looked out of place at the time.
It's got me stumped too, I guess I'll only find out where it's coming from if I strip down that part of the trans. There has'nt been any more appear since.

I'm waiting for a socket to remove the nut on the clutch now so I can strip it down and clean it up. I'm hoping the bearing will still be useable, won't know 'till I get all the grease cleaned out and re-pac it. There was'nt any play in the assembly while it was on the scoot.

Thanks guys, really appreciate being able to talk this stuff through with like minded people, and the advice and thoughts really help,
Mike

[iceman]

Belt slappage/slippage?

[Alleyoop]

Iceman may be onto to the problem. Since the scoot came with an 835-20-30 and a 842-20-30 was put on that that extra length may have caused the belt to slap on the Kickstart parts and ripping it apart.
Alleyoop

[looker]

Hi guys,
the 835 belt was the orignal one, that was changed @ 1800 miles for an 845 belt (along with new rollers) which was on there for 2500 miles. That was the belt that came off the other day to be replaced with the 842 that is in the pictures.
The 845 was changed because that is what I thought was causing the problem maybe with the slow pull away, that same problem recurred after only 5 miles with the 842 belt fitted.
Could the 842 belt really have caused the problem do you think?
I still have the 835, but I'm a bit loathed to put that on and go for a ride if it is indeed a problem with the clutch and may end up doing more damage.

I'm a bit stuck for ideas now.

I'm actually basing my assumption on it being the bearings due to the state of the grease that's left in there and something I read on Scrappydogscooters web site (from the link at the top of the screen) about someone who had the same problem and it kept happening untill he changed the clutch assembly.
Also the fact that the rear of the belt cover felt a lot hotter than the front.
The shredded belt had done a fine job of maintaining it's shape once it had cooled down and been removed, I mean to the point that if you tried to change it's shape it went back to how it looked. Again, to me it suggests heat was at play and the belt was soft and plyable and then cooled into it's current shape. If that makes sense?

Thanks guys,
I'll continue scratching my head for now, waiting for parts to come. No one seems to know much about this scoot over here even though it's gy6 based. Loads of gear available for 50cc peds

Mike

[kz1000st]

Everytime I see a shredded belt I ask the same question, "Are your rollers in correctly?" In the first picture it looks like the variator is slightly cockeyed as if the rollers are pushing the variator open at the front. If the variator is out of round it would definitely chew up the belt no matter what size it is.

[looker]

Hmmm....anyway I can check the variator while it's off?
The ramp plate (is that the right name?) is a little stiff in it's first mil or so of travel, could be the guide bushes, they don't seem to be an exact fit.
I'm looking to change the variator and clutch assembly now anyhow in the hope to eliminate any and all problem components.
Have a new bell ordered from scrappydog, just trying to find the best variator for the job while keeping the cost down if I can. I want 115mm as it has a 107mm on it the mo. I'm looking at a variator and clutch kit on ebay but it does'nt come with a fan plate and I'm havkng trouble finding one on it's own.

Thanks for your thoughts kz1000st,
Mike

[kz1000st]

Ask and you shall receive. Information that is.

www.scooterdomain.com/Variator_Fan_115mm_GY6_125_150_p/gy6vf302413.htm

[looker]

kz1000st,
thanks bud I'm looking at a complete variator from scrappydog at the moment, makes sense at this time to have a whole assembly even I only use the fan, will keep the rest as spare.

Dr. JR,

the 845 belt came with a 'service pack' (belt, rollers, spark plug, air filter....) that I bought a while back. Did'nt even realize, or know at the time, that belts came in different lenghts. It was only when I was looking to get a new belt ready for the next service that I found different sizes. Went with an 842 as it was a Gates belt and I know of that make and have had belts for different applications from them in the past and they've always been good quality. The original 835 was a Gates belt too. Was suprised to see that make of belt on a chinese scoot!!.
The 845 is made by Mitsuboshi (no, that's not a typo)!!

Thanks guys,
Mike

[sprocket]

The problem is a wrong sized belt it is hitting the kick start shaft

[looker]

Then how come the longer 845 belt that was on there for 2500 miles did'nt do the same thing

Holy cow KZ, they're qouting nearly $34 shipping to the U.K. Scrappydog only charged $14 for a bell

[looker]

So you think the angle of the 845 belt may have wore the pulley faces, and then the new 842 belt may have been sliping too far down the pulleys? I'm guessing here, but would I not have noticed some difference in pull away or top end? It all seemed the same to me.
I'll have a good look at the pulley faces tomorrow to see if there is anything noticeable.

Have a great thanksgiving guys, and thanks Dr JR,
Mike

[Alleyoop]

Also just for comparisons same thing happened to Triker98304 on his Trike you can read and see what happened to his belt in the Trike Thread.
www.scooterdoc.proboards.com/index.cgi?board=trike&action=display&thread=2288&page=1

He ordered a belt and it was a 743-20-32 belt(and not a 743-20-30) and guess what happened. Same thing as yours it ripped the heck out of it and damaged his Variator and had melted gummed up rubber stuck all over.
Alleyoop