CVT noise and wild belt vibrations
 

Hey guys, I thought I had the problem solved by simply buying a new belt, but when I ran the engine with the CVT cover off, I found there's noise without the belt hitting the CVT cover. I'm a total newbie when it comes to CVTs, so help diagnosing is much appreciated. What is that chatter that I hear? This is a 2012 Taotao ATM150-A Evo 150cc.

Here's the video of the CVT in action:

http://youtu.be/94riWeTa6Io

It seems like the rattling starts when the tire starts turning. Perhaps your gear lube is low.

Are you using the factory variator and an OEM size belt recommended by manufacturer? Can you try feeling with your fingers possible scrapes on the contact surfaces of the vario and clutch?

Remove the belt and variator and run it. If the noise persists then it's not related to the belt/CVT. If the noise goes away, then I would start looking at the clutch. It has two bearings.

IMPORTANT WARNING: Running the engine with the cover off is okay as long as you apply pressure to the kicker shaft so it doesn't vibrate out. If it does, the intermediate gear can vibrate out as well and it will shear off the variator guide rails rendering the variator useless. I learned that lesson the hard way.

Hey guys, thanks for all of the suggestions. A random check of fasteners on the bike revealed the main cause of chatter--a bolt that fastens the tail pipe to the swing arm (see attached photo). After tightening that, the noise went away. That still doesn't solve the wildly flapping CVT belt, so I'll swap the OEM belt out for a Gates Powerlink. I'll report back what I find.

Just my 2cents;
I have found that Kevlar belts are better than rubber belts.
But I have a bit of 'flap' in mine as well

The flap with a new belt is because it still wants to retain the oval shape it was in in the packaging for so long. Don't worry it's normal. As the belt breaks in the belt motion smooths out. You just notice the flapping because the cover's usually on. Out of sight out of mind.

It takes about 100 miles to break in a new belt.

Thanks guys. Got a new Gates Powerlink VE 835-20-30 on. The bolt that was chattering is now tight. All good! Everything is working great in the CVT.

That is Good News

Belt flop is a fact of life. It doesn't matter what brand you use, it's gonna happen. Think about a stretchy rubber belt getting pulled on and then compressed when engine RPM's vary slightly. The slack has to go somewhere. That "somewhere" is flop.

My VIP gy6 157QMJ Tranny case was rattling very bad. Opened it up found a casting knob broken off the case and rattling around. Its the metal square poking out just left of the clutch on the case. I don't know what broke it off. I put a new NCY tranny package in