Drive Belt Broke, Engine Stopped?

[Vision]

Today I'm heading out on an errand and there was a snap and some flopping around noise and the engine stopped. I assume the belt snapped. The engine could not be restarted. Is it normal for the engine to stop if a belt breaks? Pushing it home I could hear (probably) the clutch spinning after the bike stopped moving so I assume the belt broke. Bike has 45k on it.

Also, I assume this is how to change a belt?

[Iahawk]

I guess that method is possible in theory but I have never done it that way. I’ve always removed the nut from the variator / drive pulley. You certainly don’t need an impact wrench but if you don’t have one you’ll need some way of holding the variator while loosening the nut. You can buy cheap ‘variator or clutch holding tools’ on amazon, ebay, etc. or you can make your own out of a 24” piece of flat bar stock, 1 cut needed and 4 holes drilled.

I recall John Grinsell mentioning that he’d replaced the belt on a Helix without tools but I have’nt seen it done elsewhere.

Your first step will be to remove your CVT cover to get a look at what is going on in there.

[Vision]

I've got an impact wrench. When putting the nut back on do you need to be careful about overtightening with the impact wrench?

[Iahawk]

I’ve always used a torque wrench to properly torque the variator and clutch nuts back on. You’ll need a holding tool for that.

[Vision]

So I got everything changed and back together. Started it up and for 10 seconds was feeling pretty good about myself and then a deep rubbing sound started lightly and in five seconds was so loud I had to turn the bike off. The back wheel was not moving/barely moving. Any idea what went wrong?

[Vision]

Do rollers only go in one way? If not I'm sure I screwed that up.

[Ruffus]

No other way than to open your CVT again.
I guess you pinched your new belt with the variator fan wheel.
Or a piece of something went in your clutch.
Just open the cover and have a look.

[Vision]

I don't see how the variator could be pinching the new belt since there's a spacer.

[Ruffus]

I don't see how the variator could be pinching the new belt since there's a spacer.

Easy, during fastening front sheave, seen some already.

[Vision]

Easy, during fastening front sheave, seen some already.

What happens during fastening the front sheave that would cause this? I'd be surprised if over torqueing the nut would cause the problem. 

[Stig / Major Tom]

Sounds like your nut came off.
Watch a few more CVT youtubes - you must not pinch the belt when torque is applied - gives a false sense of tightening. (you're pinching the rubber belt - not tightening metal-against-metal)

The trick is to get the belt seated as deeply as possible into the rear pulley, first. Get it deep in there - then you will have slack in belt at the front....so tightening without pinching is possible.
What belt are you using now?
Again - watch several youtubes.
What belt are you using now?

Stig

[Vision]

The replacement is an OEM belt.

It should be fixed now. The issue was the starting ratchet wasn't seated properly with the crankshaft teeth.

An important note for first timers: once you put the variator, starting ratchet, and washer on, before tightening the nut, the rear clutch is forcing the belt backwards and therefore pushing all of the above outward, which can move the starting ratchet out of alignment with the crankshaft. You'll need to use both hands to compress the clutch to seat the belt deeper into the clutch to produce more room for the belt by the variator.

Everyone, thanks so much for the help. Looks like I'm back on the road.

[Ruffus]

The replacement is an OEM belt.





It should be fixed now. The issue was the starting ratchet wasn't seated properly with the crankshaft teeth.

An important note for first timers: once you put the variator, starting ratchet, and washer on, before tightening the nut, the rear clutch is forcing the belt backwards and therefore pushing all of the above outward, which can move the starting ratchet out of alignment with the crankshaft. You'll need to use both hands to compress the clutch to seat the belt deeper into the clutch to produce more room for the belt by the variator.

Everyone, thanks so much for the help. Looks like I'm back on the road.

I'm confused, are we talking about the kickstart ratched (pls see pic) or the variator fan sheave?
Both are in there, but as Stig already mentioned ....

[Vision]

I'm confused, are we talking about the kickstart ratched (pls see pic) or the variator fan sheave?
Both are in there, but as Stig already mentioned ....

Starting ratchet.

https://www.bike-parts-kymco.uk/catalog/Workshop-Manual/agility-125-Workshop-Manual/page100

[CROSSBOLT]

What Stig said X10:

The trick is to get the belt seated as deeply as possible into the rear pulley, first. Get it deep in there - then you will have slack in belt at the front....so tightening without pinching is possible.

More of us have devised schemes to get that belt jammed in that rear pulley.....a 50 cc is a piece of cake! 300 cc is a red-faced sweat!