Hi there..... I started hearing drive train related noises lately while my son was driving this bike. I was sure it was the chain and sprockets but after changing them all...same thing. It makes a clank clank clank noise that gets faster with speed. When I roll the bike by hand ( engine off) I can hear it click every few seconds. I removed the chain and tried the same thing, all was quiet. I revved the engine with the chain off and I can hear the clicking. ( not as heavy like while riding it)
I've never had the side covers off but think I'll have to take a look. Anyone have any idea where I should look or what it could be?

Thanks

 

driveshaft(output to drive sprocket) bearing? what color is the oil? do you see any metal shavings in the oil? so it happens when you increase torque....hmmm....

 

I was wondering if the noise is there all the time or after it warms up. i have one similar but only after 15 to 20 minutes of running? I am waiting for bearings and will update

 

If it's a CVT, I think it's the rear clutch. Maybe a spring broke.