WOW!! something is not right in your CVT that is making a lot of noise and I see that the wheel turns at those low rpms. To pinpoint where the noise is coming from take a SCREWDRIVER and touch the cover by the CLUTCH and by the Variator cover and the noise will emit to the handle of the screwdriver and that will tell you where the noise is coming from.
But you need to take the CVT cover off and VIDEO it again without the cover on it and running. And give it some throttle want to see how the belt moves in the Variator and the Clutch pulley.
Sorry to say but you do have a problem in the CVT. Alleyoop
If yours has the reverse casing on the right side like this then it takes 8oz, it is just like mine. No where else is needed the casing has a hole so the oil on the gear side that you are filling flows into the reverse casing side. Alleyoop
Well mine takes 8oz BUT mine is a Trike BUT it has the extra case for the Reverse Gears so I misspoke saying it takes 8oz's for your regular two wheel scooters. Sorry I just think of mine at times and your right HALF of what mine takes which is 4oz. Alleyoop
Yours has a CAP on it take the cap off to get at the screw.
To get rusted screws or hard to get screws out you need an impact screwdriver they work like a charm. You can set it to turn in either direction left LOOSEY or right TIGHTY and just give it a nice little whack on top NOT TO HARD just a nice little whack. I had to use it on one of my master cylinder covers to fill it with fluid.
Ok, so it is not that the idle is to high maybe it is to low to low will also cause to much vibrations from the motor. What rpms does it idle at, it should idle 1500-1800 where ever it idles the smoothest without the rear wheel spinning. If all that is good then swap out the performance cdi and plug in the Original and see if that tames the motor. If it still does it NOW you can adjust the Fuel Ratio Mixture to get the highest idle out of the adjustment. Alleyoop
Is this Vibration at a stop or as your braking to stop?
IF at a stop then: If the idle is to high you will get that through the motor the motor is being loaded down if the idle is to high it wants to turn the rear wheel.
Well if its one of your orange performance CDI's it has the timing advanced from the get go. Also with the Performance CDI, Iridium plug and coil you would need to tweak the carb some because that all would change the way your motor runs. Maybe the CDI is advanced to much don't forget all these are from china not much qualaity control (HAHA).
I cannot tell you which side is easier to get at the screw that will be up to you and what is in the way on both sides. Remember I do not have your scoot but I do know how all of them work and they all work the same way 50s, 150, 250s 300, 400s etc.. If you can work on one you can work on any of them the parts may be a little different but the same principal works for all. Alleyoop
First focus on the carb issue, and get the motor running good. The clutch is grabbing but to SOON and is causing you to lower the idle to low so the motor dies coming to stops because the idle is to low.
If you can install a Starter Clutch the pulley clutch is a piece of cake. Alleyoop
Okey, if he said all the springs are on then it has to be something else. can you do VIDEO? if so take the cvt cover off and start the scooter and video the cvt running. Or at least maybe a picture of the cvt without the belt so I can see how the belt is riding on both the variator and clutch pulley.
Something is not right in the CVT if the wheel stops spinning at 1000 rpms. Alleyoop