SAE 80W90 Heavy Duty Gear oil http://amzn.to/2uPL6TT
Chinese Scooter Service Manual https://amzn.to/2LBfWb8

This video will help you to change a gear oil on a 150 cc gy6 engine scooter.
Most scooters recommend changing the gear oil at least every 1500 miles. At the rear of the CVT on the left side of the bike there are drain and fill plugs for the transmission. Place the oil drain container under the drain plug. Now remove the filler plug first, then the drain plug and about 100 to 200cc of oil will drain out then screw the drain plug back into the transmission case. To refill the transmission, you squirt oil into the fill hole until it runs back out. That's your level check! Use the recommended oil, which in most cases is 80W90 gear oil . To get it into the small hole you need to buy the oil in a plastic bottle with a long plastic tip, which you can use to directly squirt oil to the transmission fill hole. When it starts to run back out, it's full and you can replace the fill plug .
You will need a 10mm socket wrench and about 10 minutes of your time.
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