Belt breaks and now runs rough starting from stop.

[italianmotofest]

Ok, 2006 CF Moto 250 V5. I just got this in a bike trade. The PO said that the belt broke and when he replaced it the bike will not start from a stop very well. Shakes and shudders until about 10mph. Then it runs very well.

Kind of a neat little bike. 18,000 miles.

I'm an experienced motorcyclist, but I don't know much about the CVT transmission.

Any suggestions?

Thanks!

Bill

[festus]

Hi, I've got a 2008 version of the same bike. Many times when the belt breaks, if it still has roller weights, one or more will flip sideways in the variator. This is the front pulley. If this happens I would think it could throw off the whole balance and yet still allow the bike to run but do as you describe. The tough part is that it is really hard to remove the variator without an impact wrench. Hope you have one (or access to one) Do consider Slider weights next time, they don't do that and they allow the bike to perform better at lower RPMs.

[italianmotofest]

Thank you Festus.

If I use an impact wrench do I need to have a special tool to hold it locked in place?

And, do just remove it and open it up to get to the rollers?

TIA,
Bill

[festus]

You shouldn't need any special tool to hold it. If it does try to turn, you could squeeze the belt midway with one hand or I guess use a C clamp. I didn't need to to that though.

2nd. part of your question, yes, you take off the large nut and washer that holds the variator. Then it will come apart.

It was several years ago that mine did that, and I didn't have an impact wrench at the time so it was a real pain to get that bolt to break loose. I never knew if a flipped roller caused the belt to break or if it was the other way around but I decided to go back and use sliders based on so many comments on this board about the advantages.

Lastly, be on the lookout for remains of the old belt on or around the shafts and the back pulley and clutch area. At least on mine, it was not nearly as hard to remove, but you can imagine if there is stuff in there that doesn't belong that would cause jerky-ness as well.

[italianmotofest]

Great tips.

Thanks for your reply. I hope to tear into it tomorrow.

Bill

[bnc]

I can see if the belt breaks, the movable variator face might be able to move towards the drive pulley face enough for the rollers to move around or may be even fall out but not sure how a person replacing the belt could do that.

The rollers are bigger in diameter than they are wide so they can only sit down in the roller channels one way. I tried putting a roller rotated 90 degrees in the channel and it just sits on top and won't drop down in any position at all. The roller would ride so high that it would be really tough to get the belt on and if it could be done, the belt would be forced into the outer most edge for the drive pulley.

[italianmotofest]

Festus, you were right!

It does appear that when the belt broke it allowed the worn rollers to move out of place. They were all worn down on one side. I dressed them a bit rounder with a file. The bike runs great!!

It took me longer to replace the belt cover with the gasket than pulling and fixing the rollers!

Seeing how worn the rollers were, I think I should replace them. Can you point me to the set of sliders that you used? There are just WAY too many options for rollers.

Thanks again,

Bill

[bnc]

Not to doubt you guys but I don't see how it is possible to have roller in a slot rotated with a new belt on.

The left roller in the photo is rotated 90 degrees and it will not go down into the roller slot, leaving it higher than the highest possible position for a roller that sits in the channel like the one at the bottom.

If it sits that high, it would make it really difficult to get the belt on because it is pressing the two drive pulley halves together tighter than if you were in high gear. Maybe it could be done by brute force, lol!

[italianmotofest]

Well... These rollers were in pretty bad shape. Very worn.

When I removed the variator, I made sure to keep it intact so I could inspect it. Sorry I didn't get any pics. Anyway, some of the rollers were not oriented where they should have been. The edge of the plastic was chewed up and the round face had big flat spots.

I'm guessing that when then belt broke it allowed the worn rollers to get beat up. Then when the prior owner put the new belt on he only removed the outer plate and perhaps was able to get the nut started and pressed the outer plate on with the nut.

Or, when I take a longer ride it's still all screwed up and I'll have to fix it again.

Only time will tell!

Either way, I'm going to install new rollers or sliders.

Thanks to both of you for your replies. I really do appreciate all input.

Bill

[festus]

that's exactly it bnc the installer didn't do it, the belt breaking (at speed) did it. And when I said "flipped sideways" I should have said improperly oriented or rotated. I'll do a little searching for sliders and post that in a few if the search goes well. Hopefully I can look in my records and see what I settled on for sliders. The first set cost me too much torque on take off. Back soon I hope.

[festus]

http://www.partsforscooters.com/169-...Roller_Weights

There you go. The bike came with 26 gram, but I eventually went down to 24 gram. You see, the heavier you go with the rollers or sliders the lower your RPM will be at top speed and in theory, you may be able to go a little faster but as I said using 28 gram 23mm X 18mm sliders (recommended) I felt that I had lost too much take off speed and I was afraid that might get me in trouble getting out of the way if I had to. So after my experience, I would suggest 24 - 26. You will find it transitions much more smoothly and may get even better mileage.

[italianmotofest]

Thanks! That's what I'll get.

Again, thank you for your help.

Bill

[italianmotofest]

Went for a forty mile ride today. Runs great!

Sliders ordered as suggested.

Thanks,
Bill

[Maddog]

I've seen times when the belt takes weeks of shredding before it finally breaks.
The symptoms mimick a variatior problem. The acceleration is sluggish and it seems to creep at idle speed. This is caused by rubber build up in the centrifical clutch drum. The clutch engages early because of rubber build up. If the belt is badly shredded, remove the clutch drum and blow out debris, also blow out all the nooks and crannys. If chunks of the old belt are pocked up in the new belt it will have you scratching your head. Just a heads up!

[italianmotofest]

Thanks for the tip.

Bill